Failed to create the two rasterize functions

- draw .c/h rasterize functions are coded but there's a core dump
- main.c old code is commented, try to call drawing_rasterize
Added debug symbols when building

Added -ggdb in CFLAGS in the Makefile.

Signed-off-by: Celelibi <celelibi@gmail.com>
Allocated the default drawing

Instead of making the global drawing a pointer, it's now a struct.

Signed-off-by: Celelibi <celelibi@gmail.com>
Don't crash when the polygon list is empty

Test the first pointer instead of the next one, so that the empty get
drawn correctly (not drawing anything).

Signed-off-by: Celelibi <celelibi@gmail.com>
New function for allocating a new polygon

This function append the new polygon to the list and set it as the
active polygon. The active polygon is the one the user is working on.

Signed-off-by: Celelibi <celelibi@gmail.com>
Use the active polygon

The active polygon is the one the user is working on. It's not
necessarily the first polygon in the list.

Signed-off-by: Celelibi <celelibi@gmail.com>
Don't remove the polygons rasterized

We need to keep them around since they will be rasterized a lot if time.

Signed-off-by: Celelibi <celelibi@gmail.com>
Merge branch 'rasterize'

Signed-off-by: Celelibi <celelibi@gmail.com>

Conflicts:
	draw.h