added dependency on python-ghostscript.

[PythonCHB]

Here's a PR for the dependency on the new python-ghostscipt package.

This should create a camelot conda package that works out of the box.

I also added a test that runs camelot against a pdf file, to make sure that it actually works.

I added an exampel odf to the recipe for the test -- I copied it from the source.

You should be able to pull that file from the source in the recipe, but I couldn't get it to work, so I did it this way.

This should fix #25

[conda-forge-webservices]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.