Improved test sandbox execution.

Now the test runner doesn't load my plugins from ~/.vim/plugins (which
is where I keep quite a bit of my configuration).
Corrected buffer creation / nuking.

This fixes #23
Added travis specific test config.
More test runner tweaks.
Swapped back to normal build again.
Swapped to develop run.
Removed use of quit and reverted travis specific run
Simplified even more. I have no idea what's making travis fail :(
Added ! to new enmasse window.
Merge branch 'feature/fix-new-buffers' into develop