Merge pull request #178 from kigeia/unstable

Add label prediction in seach results
setup.py: check non-setuptools dependencies first

Signed-off-by: Jerome Flesch <jflesch@gmail.com>
README: Add infos regarding some depencies

Signed-off-by: Jerome Flesch <jflesch@gmail.com>
Optimization of label prediction :
	save the thumbnails for pdf (refactor thumbnail cache code)
	save the doc prediction features in cache files in the papers directories
	use compress = 0 for saving prediction objects
	tune the granularity of the fitting methods
	tune the search results with prediction labels and date sorting