Add command line options.

[63BeetleSmurf]

This pull request adds new command line arguments allowing for creating new notes and toggling note visibility. This is useful for creating keyboard shortcuts.

$ sticky --help
Usage:
  sticky.py [OPTION…]

Help Options:
  -h, --help                 Show help options
  --help-all                 Show all help options
  --help-gapplication        Show GApplication options
  --help-gtk                 Show GTK Options

Application Options:
  -a, --autostart            Autostart mode
  -n, --new                  Create a new note
  -t, --toggle               Toggle note visibility
  --display=DISPLAY          X display to use

[clefebvre]

Very nice.

[clefebvre]

Merged on master.