WIP version of the OptimizeGraph-Step.
Added hashes to some string routines (speedup).
Improved property system for float and strings.
Refactoring code for computing normals from smoothinggroups.
Implemented C-ASSIMP.
git-svn-id: https://assimp.svn.sourceforge.net/svnroot/assimp/trunk@116 67173fc5-114c-0410-ac8e-9d2fd5bffc1f