Blender Git Loki

Cleanup: Move modal operator draw callbacks out of ED_gpencil.h

Turns out that these were only actually used from within the gpencil
module (i.e. they were defined in drawgpencil.c, and called from the
gpencil_<opname>.c files), so it's not even necessary to export these
function prototypes in the ED_gpencil.h header.