Fixes in btContinuousConvexCollision, should fix Issue 347

Continuous sweeps do not detect hits unless body0 and body1 penetrate more than allowedCcdPenetration.
This is to allow sliding objects (characters) where otherwise any contact would result in TOI = 0.
If objects penetrate deeper than allowedCcdPenetration at the start of the sweep, a TOI=0 is reported, unless the motion will separate the objects.

Secondly, a reportFailure method is added to CastResults, to handle failures gracefully (in case max iterations of conservative advancement is reached etc)

src/BulletCollision/NarrowPhaseCollision/btConvexCast.h

@@ -39,7 +39,7 @@ public:
 				
 		virtual void	DebugDraw(btScalar	fraction) {(void)fraction;}
 		virtual void	drawCoordSystem(const btTransform& trans) {(void)trans;}
-
+		virtual void	reportFailure(int errNo, int numIterations) {(void)errNo;(void)numIterations;}
 		CastResult()
 			:m_fraction(btScalar(BT_LARGE_FLOAT)),
 			m_debugDrawer(0),