First commit

Implemented stub widget based on 'zsh-users/zaw'
Implemented stub background source
Improved source select handler

- Now uses nulls as command separators instead of newline characters
  (In the future we should also handle filenames with newlines)
- Handling $BUFFER size when marking line cursor
Implemented basic file glob source
Improved ipc code
Updated README
Fixed the default keybind
Changed default keybind
Fixed glob construction bug
Updated README
Added hooks for delete/backward-delete widgets
Added stub implementation of match highlight
Added simple match highlight to the results
Implemented 'accept-line' handler
Fixed bug in 'accept-line' handler
Improved filename highlight and updated README
Fixed ignore file parsing bug
Update README.mkd
Updated README with shelr demo
Merge remote-tracking branch 'origin/master'