Add redis and mongo to travis build
Only support php 5.4 and up
Cannot get mongo to work with scrutinizer.

It either complains about the extension not being present when we don't install it, or already being installed when we try to install it.
There is a hint in one of the logs that it could be an incompatibility with the analyzer and php 5.4.
Merge pull request #1 from gaillard/master

Add redis and mongo to travis build