bump recommended Ruby version to 1.9.3-p448

See http://www.ruby-lang.org/en/news/2013/06/27/hostname-check-bypassing-vulnerability-in-openssl-client-cve-2013-4073/
Drop weird stop in conversations controller spec
... and make the specs actually pass
Install strong_parameters
Strong parameters for Aspect
Remove a duplicated test.
Remove tests for strong parameters
Strong parameters for Block
Strong parameters for Conversation