Deal with broken DNA serialization. Bullet 2.76 release revision 2035 - 2046 was broken, and this includes the Maya Dynamica plugin.
Added some workaround to deal with the broken .bullet files, instead of crashing.
Introduced generated unique id's, instead of the pointer address to avoid 64bit->32bit truncation issues
Use serializer->getUniquePointer instead of directly using a pointer
moved ChunkUtils::getNextBlock to bFile::getNextBlock.
Moved 'TEST_BACKWARD_FORWARD_COMPATIBILITY' to bDNA.cpp. Enable the define for further testing of .bullet format
Removed duplicate definitions and use the one in LinearMath/btSerialization.h
