Bug fixes

• Fixed bug in Indexify function that caused it to be really slow when passing 10K identical vertices. Also fixed a problem that could have led to some vertices not being welded.
• Fixed bug in SixDOFConstraint::RestoreState that would cause motors to not properly turn on.
• Fixed a determinism issue in CharacterVirtual. The order of the contacts returned by GetActiveContacts() was not deterministic.
• Fixed issue in sample application that mouse is very sensitive when viewing with Parsec.
• Support for compiling with ninja on Windows.