.cache() with no ops now sets them to full regardless of other params

Previously .cache(timeout=SOME_VALUE) left ops unchanged.

Conflicts:
	CHANGELOG
Fixed bug with schemes unsync when invalidating model

Just don't clear model schemes on model invalidation anymore.
Updated LICENSE
Fixed bug with negated "some"-condition, found in #75
Test for invalidation of queryset with fuzzy condition
Fixed caching if empty queries
Upped to 1.3.1
A tiny refector in file cache

Ensure file is closed in FileCache.get() using with.
Updated features list
Added a couple of TODOs
Merge branch '1.x'

Conflicts:
	CHANGELOG
	README.rst
	cacheops/invalidation.py
	cacheops/query.py