update README update Doxygen docs scons option 'msvc' changed to 'mingw' as msvc is default and mingw must be turned on explicitly

more build script tuning make all float constants single precision solve many warnings from msvc and gcc with various -W... flags add common.cc file for dbgmsg() function witch apparently cannot be inlined fix python module building with msvc, add manifest file handling remove forgotten RenderrowData class add stanford models download script for windows (.bat)