Added support for the Cm_Cache_Backend_Redis

Might need some refactoring.. maybe we could consider splitting up the
cache interface into 2 types: opcode caching / object caching? Because
now there is some useful information missing. Or alternatively we could
add a generic function which could return a key-value array of
additional information to be printed in the list
Forgot to remove Mage::log statement
Refactored local.xml to Mage::getConfig for memcache & redis
Merge branch 'develop' of git://github.com/jasperdcbe/Hackathon_MageMonitoring into jasperdcbe-develop