[FIX] memcache: Cache and restore javascript and css added to headerlib during page rendering (by plugins etc). Should be generalised and refactored into headerlib when not in freeze.

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/11.x@46317 b456876b-0849-0410-b77d-98878d47e9d5
[FIX] memcache: Flush memcache when flushing other caches

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/11.x@46318 b456876b-0849-0410-b77d-98878d47e9d5