Corrected logic issue in ijkIndex, and fixed some 64bit mode warnings.

If you immediately compared an ijkIndex after constructing it, you would
get the wrong value. Also extended ijkIndex to be able to compare against
other ijkIndices, and made it easier to construct ijkIndices.

Also added support to compare ijkIndices against other ijkIndices.
Cleanup BindKeyGroup and KeyGroup so that KeyGroup has its own header.
Cleanup the names of the helpers for the Reduce Keys scheduler.

The helper header needed a better name, and the class should match
the header name.
Use dax::Ids everywhere, so that we properly compile with 64bit ids
Fixup with 2 back, rename commit.
fixup exec keygroup with missing header.
Again correct the CollectCount worklet to properly collect counts.

I made a mistake and forgot that CollectCount has a different instance
for each item in the parameter pack.
Merge branch 'correct_64bit_issues'