The present invention relates to a kit for use in the course of hanging a door. The difficulties associated with fitting a door are apparent to anyone who has attempted the challenge. The problems arise from single-handedly trying to work on the door whilst simultaneously trying to support the door on edge, or in an upright arrangement when positioned within the door frame. The size of most doors and the need for an exact fitting often renders the exercise too difficult for one person. A number of devices are known, or have been proposed hitherto, for alleviating the problems outlined above. Such devices are variously complex in construction, difficult to use or of limited effectiveness. I have now devised a kit for use in supporting a door on edge whilst planing it to size and/or cutting the recesses required for fitting its hinges, and for use in aligning the door when positioned within a door frame, in the course of hanging the door, the kit being of simple and compact form and easy and convenient to use. In accordance with the present invention, there is provided a kit for use in the course of hanging the door, the kit comprising a block which is formed with a transverse slot into which an edge of the door may be engaged, a first wedge for insertion into said slot against a face of the door in order to hold the door firmly in said slot in vertical orientation, and a plurality of secondary wedges for insertion into the gaps between the edges of the door and the door frame for aligning the door when positioned within the frame, the wedges being arranged to be engaged, when not in use, in or to said block. Preferably the block is formed with one or more recesses into which the wedges are received when not in use. Preferably a first recess is provided for receiving the first wedge, and a second recess is provided for receiving the secondary wedges. Preferably the first recess is formed in the upper side of the block, adjacent one end thereof. Preferably the second recess is formed in the upper side of the block, adjacent the opposite end thereof. Preferably the first wedge is retained within its recess as an interference fit between opposite sides of the recess. Preferably the first recess has a sloping bottom surface, arranged for this recess to receive the first wedge with an inclined face of the wedge against the sloping bottom surface of the recess. Preferably the second recess is arranged to receive the plurality of secondary wedges when positioned side-by-side, preferably retaining these wedges as an interference fit between opposite sides of the recess. Preferably, the second recess has a sloping bottom surface, arranged for this recess to receive the secondary wedges with inclined faces of the respective wedges against the sloping bottom surface of the recess. An embodiment of this invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is an isometric view of a door support and alignment kit in accordance with the insertion, shown with its wedges stored in recesses of the support block; Figure 2 is a similar view of the kit shown in exploded form; Figure 3 is a side view of the kit as shown in Figure 1; Figure 4 is a plan view of the kit as shown in Figure 1; and Figure 5 is an isometric view of an edge portion of a door being supported by the support block of the kit. Referring to Figures 1 to 4 of the drawings, there is shown a door support and alignment kit which comprises an elongate block 10 which is rectangular in plan view, side view and cross-section and is formed, intermediate its opposite ends, with a transverse slot 11. The slot 11 extends downwardly from the upper surface of the block 10, to leave a relatively thin web 10a the flat upper surface of which is parallel to the underside of the block 10. The slot 11 is defined by end surfaces 11a, lib which are perpendicular to the upper surface of the block 10: and surface 11a is perpendicular to the opposite edges of the block 10, whilst end surface lib is inclined at an acute angle to the end surface 11a. The block 10 is formed with two recesses 13, 15, the recesses 13, 15 being formed in the upper surface of the block 10 and extending to the respective end faces of the block. The recesses 13, 15 have bottom surfaces which slope downwardly towards the respective end faces of the block. Recess 13 receives a single wedge 12 and this is retained in the recess as an interference fit between the opposite side surfaces of the recess. Recess 15 receives a set of four wedges 14 positioned side-by-side and retained in the recess 15 as an interference fit with each other and between the opposite side surfaces of the recess 15. When positioned in their respective recesses the wedges have their sloping faces against the sloping bottom surfaces of the recesses, their opposite faces flush with the upper surface of the block 10 and their end faces flush with the end faces of the block 10. Figures 5 shows the block 10 being used to support a door D on edge, to enable the edges of the door to be planed to size and then recesses for its hinges to be cut out. The door D is stood on edge, engaged in the transverse slot 11 of the block 10 and rested on the upper surface of its web 10a: the wedge 12 is slid into the slot 11 alongside one face of the door D, in order to wedge the door against the end surface lib of the slot 11, and so hold the door in a vertical orientation. The block 10 thus forms a sturdy support for the door D, such that the edges of the door can be worked on. Once the door has been planed to size, it can be positioned within the door frame and the smaller wedges 14 can be inserted into the gaps between the edges of the door D and the frame, in order to align the door precisely within the frame, and ensure consistent gaps around the edges of the door, before the door and frame are marked out for the positions of the hinges and door catch or lock. It will be appreciated that the kit which has been described enables the wedge 12, required for the support of the door on edge, and the wedges 14, required for the precise alignment of the door within its frame, all to be stored in convenient manner when not in use, in the support block 10.