Basic testing of RGB support
Merge pull request #5 from jbrooksuk/rgb-support

Basic testing of RGB support
Make it easier to edit the GutterColor settings
Created a foundation as to install instructions
Added a command to clear the cache manually
Clear command should force clearing of cache
Improved install message
Merge pull request #8 from jbrooksuk/clear-cache-command

Clear cache command
Merge pull request #7 from jbrooksuk/install-message

Install message & menu settings item
Tweak the RGB regexp.
Ignore TypeError.
Clean up Line class.