Removed the BC layers for Symfony 2.2 and older

[stof]

Symfony 2.2 is EOLed since 1 year: http://symfony.com/roadmap?version=2.2#checker

I think we can be fine with dropping the support for it in the next minor version of the driver (1.3.0) rather than bumping the major version.

People using Mink inside Behat already lost the compatibility with these unmaintained Symfony versions anyway btw, and I don't think anyone should be using unmaintained versions, so it is acceptable IMO (people who don't update their Symfony dependency will be fine with not updating their Mink driver anyway)

[stof]

note that we already dropped the testing for these versions a while ago (we rely on Silex for the testsuite, and it does not support these Symfony versions anymore)

[stof]

This is a cherry-pick of the second commit of #44 btw.

[aik099]

I think, that first we need to release next minor driver version with update for supporting new findElementXpaths method. Then we can merge this PR (no need to release immediately after this PR is merged).

[stof]

@aik099 do we need 2 different minor versions for these ?

[aik099]

I'm not sure at 100%. Removing compatibility is BC break after all.

[stof]

@aik099 I'm removing the compatibility for versions which are unmaintained since more than 1 year (I'm talking about the end for security maintenance).

[aik099]

OK.