add tests with extension, add 5.5, remove old 5.3.2

Also increased sleep time since sometimes Cassandra was not up yet when tests fired!

You can check that the extension is actually installed looking at:

https://travis-ci.org/ricardclau/phpcassa/builds/9637479 (you can open php -m output to check that thrift_protocol is actually installed)
https://travis-ci.org/ricardclau/phpcassa/builds/9637697 (this is the actual PR)

Please check that I am not missing any parameters while building the extension