EditMesh *EM_GetEditMesh(Mesh *me);
void EM_EndEditMesh(Mesh *me, EditMesh *em);
as discussed on the mailling list, this is to facilitate migration to bmesh.
next step is to merge this this to the bmesh branch. this was done in the 2.5
branch to prevent too great a divergance.
also, made makesdna/makesrna work on cygwin/msvc2008/scons.