Import of NetGen 5.1 taken from http://sourceforge.net/projects/netgen-mesher/files/netgen-mesher/5.1/netgen-5.1.zip/download
Allow building without zlib (if defined NO_ZLIB) and threads (if defined NO_PARALLEL_THREADS)
Porting to OCCT 6.5.x..6.7.x
Avoid compiler warning
Adding VC++ 11 (VS 2012) projects for nglib
Add .gitignore
VS projects reconfigured

- project options are aligned with usual OCCT settings (/EHa)
- binaries and libs are put to win32... and win64... folders
- headers are copied to include folder
General fixes: exit() replaced by exception throwing to avoid sudden application exit; while (1) replaced by for (;;) to avoid compiler warning
Avoid compiler warning in header when NO_PARALEL_THREADS is defined
Export OCCGeometry class to make OCC interfaces usable outside
Fix problem of extra face descriptors
OCCLIBRARY macro added to enable link with OCCT
Made fixes for meshing of OCC shapes.
OCCSetLocalMeshSize function optimized.
Removed some commented lines.