Could make nightly env files more easily usable
It would be good to make nightly environment files something people don't have to consider:
- Expand the default set to cover debug/release/both builds
- Expand the search path to include (probable) $WORKSPACE/env/...
- Set default package versions based on a date stamp such that people ideally don't need to consider it any longer.
This, in tandem with changes made previously to make the default env file guess CODEMGR_WS and set a sensible version string, should mean that for almost any user 'nightly debug' or 'nightly release' while in a workspace is all they need to think about.