findTriTriDistance( const Triangle3& a, const Triangle3& b )

[Fedr]

1. Deprecate triDist functions, and introduce instead two findTriTriDistance functions for float and double precisions with more convenient interface. Replace deprecated calls with new ones.
2. The implementation of new functions was significantly rewritten: magic constants eliminated, repeating code is replaced with one internal function double call.
3. overlap flag exposed to distinguish between real intersection and just a touch.
4. Added calls from doTrianglesIntersect test.