[mms] Add MongoDB driver.
Add doc example
For clarity, use constants to identify mongo field names
We should be checking framework level mongo drivers in Horde_Core, not horde
Fix mongo cache driver recognition in IMP
Really no reason not to be compressing pages - with todays CPUs, overhead is inconsequential
[mms] The history driver can now be configured via conf.php.
[mms] Add a NoSQL driver for history storage.
[mms] Support new configuration options for history storage.