remove uses of the nimble namespace, as we move towards nimble2

[perrydv]

I am not sure if this is ready to merge, but let's see if it passes testing and any input from @paciorek.

This simply comments-out the use of nf_changeNimKeywords, pending discussion of where that should be done. (See #60).

I think calc_dmnormAltParams and calc_dwishAltParams will both work as nCompiler::nFunction. However full testing will really come from uses in nimble2.

[paciorek]

Ok I did some work to address some of the test failures. This was done with a bit of duct tape and chewing gum to get things working in terms of transitioning to nC and nMul, and now using nCompiler:::nf_changeKeywords.

There are still some modelValues test failures plus a failure with test-setupMargNodes caused by the keyword changes inserting dexp_nCompiler but that seemingly not fully functional.