Revert "Design: removes circular dep. between pyphant and ImageProcessing"

This reverts commit 63123a48bc4c47b59699e0cfa1433bdce1a59d66.

Conflicts:

	src/pyphant/pyphant/tests/TestCompositeWorker.py (not reverted)
	src/pyphant/pyphant/tests/TestParam.py (not reverted)
	src/workers/ImageProcessing/ImageProcessing/ImageLoaderWorker.py (merged manually)

Signed-off-by: Alexander Held <alexander.held@fmf.uni-freiburg.de>
Fix: fixes #19

* adds PIL dependency to pyphant.imageprocessing
* adds `pkg_resources.require(...)` to cli (cli is not a package)
Merge pull request #34 from aheld84/master

Fixes #19