Parse any arbitrary Reply and store information in 'contain'.

With this improvement, any arbitrary Reply received by parser would store internal data in `contain` attribute and root element name in `containName` one.

As diff between original `TransportContentParser.java` and new one is not very well printed by GitHub, I generated this better [view](http://www.diffnow.com/?report=eyv4u).

Fixes [OPENNAAS-1437](http://jira.i2cat.net/browse/OPENNAAS-1437).