Support multi app and multi cache (fix #53)
add a SpreadSASLMemcached

Create a backend that has the ablity to spread value across
multiple keys if it is bigger than the memcached treshhold
which by default is 1M.
cache more set/get exception in backend
finish spread backend, and test
added option to connect to Redis server using Redis URL
Keep the cache exception context.

This will keep around the context, and location, of the original exception.
Concat jinja2 keys together. Refs #27
Delete memoized verhash function
Merge branch '53_multicache' of https://github.com/methane/flask-cache into methane-53_multicache

Conflicts:
	flask_cache/__init__.py
Merge pull request #56 from Carreau/spread-cache

Add a SpreadSASLMemcached
Documentation
Merge branch 'catch-fail-setget' of https://github.com/Carreau/flask-cache into Carreau-catch-fail-setget

Conflicts:
	flask_cache/__init__.py
Fix delete memcached memver and added unit test
Small timing problem when running on travis server
Merge pull request #59 from streeter/patch-1

Keep the cache exception context.
fix new except cases, refs #59
Merge pull request #61 from iromli/redis-url

Redis URL Support
Added unit tests for redis url
Assert that the memhash did in fact get deleted
Remove bad copy paste :p