Fix shadowed variable 'facets'
Fix gitignore for sln/vcproj

 - The DevStudio/msvc build does not work for shared libraries (dll)
 - Fixed QhullFacet::PrintRidges to check hasNextRidge3d()
 - Cleaned up Qt project files
 - Fixed Makefile for shared libraries
 - Moved libqhull to libqhullstatic, as done in CMakeLists
 - Made libqhull a shared library
 - Restored /INCREMENTAL:NO since CONFIG -= incremental did not work
 - Added 'facets' argument to user_eg3.cpp

Need to update .pro and build files.

- qh-optf.htm: Add note about order of 'Fn' matching 'Fv' order [Q. Pan]
- Add .gitignore with ignored files and directories.
-   Use .git/info/exclude for locally excluded files.