2.0 release

2.0 release of assimp2json, based on the current (2013-10-06) trunk of assimp: https://github.com/assimp/assimp/tree/7a4edbd1265d9dc9e65b96dc750291dd43288fea

Notable changes include a proper build system, Win32 binaries and better default settings for the assimp import.

Have fun and don't forget to file any bugs you may encounter.