Merge pull request #20 from jb098/dev

Overridden __invert__ to be able to use ~ on operators. nb care must be taken with finders that are passed to this,in the case where they find multiple things.
Up version.
Allow Fake Backend to take an image as the screen
Merge pull request #21 from ant1441/fake-backend-image

Allow Fake Backend to take an image as the screen
Fix bug in SliceFinderFilter repr
Pushed 1.0a9 to PyPI.
Fixed bug with exact finder