- solidify/Makefile (OBJS): added overlap.o
- solidify/Makefile (CFLAGS): added -O9 to speed up rotation a little
- solidify/array.h, solidify/array.c (get_bounded): like get(), but returns
UNDEF if the indices are outside the array
- solidify/face.h (struct face, struct matrix), solidify/face.c (read_file):
added a 2D transformation matrix to "struct face"
- solidify/overlap.h, solidify/overlap.c: show a face with 2D transformation
- solidify/face.h (struct face), solidify/face.c (read_face),
solidify/level.c (draw_map, draw_image): introduce inclination of the z0
plane
- solidify/level.c (draw_map): make blue z == z0 display more continuous
- solidify/level.c (scroll_event): moved z0 shift to scroll_z
- solidify/level.c (scroll_event, scroll_xy): added manipulation of the
z0 plane's inclination
