Project cloning - allow for remote origin

- Add fine control over which repos in the origin get cloned via a
  GTWS_PROJECT_REPOS variable.
- Use this setting in an example clone function that clones from a
  remote origin
Cleanup - Prefix GTWS on WSPATH and WSNAME

- Rename WSPATH to GTWS_WSPATH and WSNAME to GTWS_WSNAME
- Export them for use in scripts/shell
gtwsrc - export LD_LIBRARY_PATH and PYTHONPATH to make per-WS installed packages runable.
gtwsrc - comment out per-project examples
gtwsrc.project - make tags in src/, if possible