added TCompare template param.

TCompare apply to the compare template param of std::set.
constructor take default constructable comparator
Merge branch 'master' into exposeCompareInDigitalSetBySTLSet
strict type for external operatio
changelog
viewer accepts custom DigitalSetBySTLSet
oups
Merge pull request #722 from elcerdo/exposeCompareInDigitalSetBySTLSet

Expose compare in digital set by stl set