refactor interfaces:
* remove code duplication (cached_function vs cached_method etc)
* cleaner internal function definitions
* update tests
* add django 1.6+ feature awareness (never set explicitly timeout=None)
* add django 1.7+ caches dict support
update tests (add staticmethod test) and docs
update docs: reST, to use with sphinx
add sphinx docs
keys: use unicode literals and force_unicode to avoid argument variance by string types
keys.make_key_for_group: use str.format instead of %
keys.make_groups: add __qualname__
fix memcached key encoding unicode->utf8
Merge branch 'develop'