"better" (Rails-aware) RUBYLIB when running `rake rails:test`
require mocha from tests insteda of from Bundler
thus we avoid a deprecation warning with Mocha 0.13
setup activerecord/test dependencies into a rails group
(based on Rails/ActiveRecord 3.2.9)
unfortunately we need to declared actionpack due session tests
simply adding it into the RUBYLIB (from rails.rake) when running rake rails:test would get a bit complicated since there's a lot of versioned deps for the gem such as rack and others ...
we shall setup the connection methods when adapter is loaded
this is relevant when using the 'jdbcxxx' adapter AR than attempts to require the adapter file and expects a jdbcxxx_connection method to be available on AR::Base

this reverts 20522b6ce39a4a9d9c4aaade461b4480ef5a4ae7
but on the other hand jdbc- gems should get required (for now when establishing the connection) with the possibility to work even when the driver gem is not-available and the .jar is on CP
Merge pull request #289 from kares/rails-tests

setup the connection methods when (jdbc) adapter is loaded