* Use ARB_ and arb_ as variable prefixes in place of NMC_ and nmc_.
* Replace references to 'NestMC' and 'NEST MC' to refer instead to Arbor.
* Use 'arbor' as the sim name in generated validation data.
* Reflow long-line paragraphs in `tests/ubench/README.md`.
* Change names of CUDA mechanism and CUDA kernel libraries to include arbor name.