gtws-examples - Some nice fixes

- Have project auto-detect it's name, to avoid editing each time
- Set debug symbols for CMAKE
- Set default project to cohortfs
tmux - cleanup and improvements to tmux handling

- Move tmux code into library, to allow central control and use in more
  scripts.
- Enhance tmux lib to handle attaching vs slaving
- Make tmws attach to the primary session if it's detached, or slave
  otherwise