make groups and accounts reachable from tenants
add ability to resend email verification tokens
Merge pull request #99 from denibertovic/develop

verification emails and make groups and accounts reachable from tenants
Adding info about new feature.
some prospector cleanup
added memcached cache backend
add doc strings for RedisStore
fix tests failing for py <= 3.2
Merge pull request #100 from denibertovic/memcached

Add memcached cache backend
Adding changelog info.
Adding release date.
Version bump.