WIP Adding more graphical projection drawing tools

Stubbing out tools for drawing in axonometric projection -- Isometric,
Dimetric, Trimetric -- and in oblique projection.

Also, placed 1-, 2-, and 3-point perspective tools, along with these
new ones, into a new Magic Tool group, MAGIC_TYPE_PROJECTIONS.

See https://sourceforge.net/p/tuxpaint/feature-requests/252/
and https://sourceforge.net/p/tuxpaint/feature-requests/253/

src/tp_magic_api.h.in

@@ -183,6 +183,7 @@ enum {
   MAGIC_TYPE_PAINTING,
   MAGIC_TYPE_PATTERN_PAINTING,
   MAGIC_TYPE_PICTURE_DECORATIONS,
+  MAGIC_TYPE_PROJECTIONS,
   MAGIC_TYPE_ARTISTIC
 };