Revert "Use Memcache and clean up caching setup."

This reverts commit 728e5bc83ca6fc023f90d6b9745e12f4601f85de.

Conflicts:
	settings.py
Merge pull request #1881 from groovecoder/revert-memcache-setup

Revert "Use Memcache and clean up caching setup."
 Use Memcache and clean up caching setup.

- remove django-cache-machine

- removed secondary cache alias again

- use Django's cached_property decorator instead of own

- updated constance's cache setting to last format

- django-memcached-hashring for consistent hashing (based on python-memcached)

Fixes #1780.

This reverts commit b9c6776a23880cecf20bca0d42b710997c7bdb0b.