When curve objects have no front/back faces, the bevels were only drawn
for the outer part. Now it also makes interior bevels, so yo can
have a curve become a 'solid' ring easily.
Note: only works when you disable filling option "Front" and "Back".
NOTE: BLI_winstuff.h was meant to be a wrapper around windows.h to handle
undefining various crap that windows.h defines. Platform specific headers
should only have to be included in a few places. This reduces the number
of inclusions of BLI_winstuff.h to 16 which is a much more reasonable
number (than the 144 or whatever it used to be)
different objects shouldn't share flags this way (still sharing of
other mesh flags in renderer... ickity pickity, but I'm not fixing now)
- removed some unnecessary uses of DNA_mesh_types.h
