Fixed opening non-existant paths.

Trying to open non-existant paths would give a python error.
Now displays a message in the status bar instead.
Added message when trying to complete to missing files.

Also removed print statement that was left over from debugging.
Merge branch 'develop'
Added ability to create paths that don't exist.

Also a few bug fixes.
Updated readme to include information about path creation.
General code cleaning and improved behaviour of path creation.
Merge branch 'develop'