The GTest framework has a more active support base, and natively
supports CMake. Introduce it as an external dependency (using CMake's
ExternalProject_Add), replacing cppunit and porting the associated unit
tests.
- implement ExportToBlob/aiExportToBlob via a custom IOSystem implementation.
- split exporter C and C++ interfaces.
+ test cases for the exporter interface
git-svn-id: https://assimp.svn.sourceforge.net/svnroot/assimp/trunk@913 67173fc5-114c-0410-ac8e-9d2fd5bffc1f