Fix usage of CompareFirst/SecondBodyName return value

[Puttichai]

Summary

The recently added CompareFirstBodyName and CompareSecondBodyName functions in CollisionPairInfo return 0 when the given string compares equal to the first and second body names, respectively.

There are some places that expect to test for equality but are missing the test == 0.

For example, in StateCheckEndEffector::_CheckCollisionPair, the condition reads

if( !!pbody && cpinfo.CompareSecondBodyName(pbody->GetName()) ) {

while the original code reads

if( it->GetBody() == pcolliding ) {

[rdiankov]

thanks!