Add functions for clearing saved workspaces

Automatically clean up register list when buffers are killed
Bind wacs-main-buffer for use in auxiliary function conditions

Not yet tested
Update README to discuss path helper functions
Optionally save frame position

Don't bother with registers--just use current-window-configuration or
current-frame-configuration.
Update README to talk about saving window configuration
Keep frame configuration lists clean
Change shell buffer name
Tidy up source code a bit
Mention wacs-clear-all-saved in README
Version bump: 0.3
First attempt at travis integration
Make run-travis-ci.sh executable
Include build status button in README