handle some keywords and some other misc stuff - #62

This is turning out to be a PITA (in light of things to be dealt with in issue #60 ).

So let's not merge this. I will come back to the core of this PR, supporting for(i in c(2,3,5)) and y[c(2,3,5)]~dmnorm(...) once we deal with issue #60.

The handling of nC was done in the work to remove dependence on nimble.

The work in commit 9b178ca on using integer type for nodeIDs was "handled" in resolving the merge conflicts in switching to main from master in commit 3f521b7. It's not clear to me what happened, but things seem ok now.