Override assertTag and assertNotTag to remove deprecation errors

[enov]

When running Kohana test suite with newer PHPUnit the assertion
methods assertTag and assertNotTag raise deprecation errors.

This is a patch to avoid the errors until phpunit-dom-assertions
gets released which should provide alternatives.

[enov]

@acoulton you probably did not like this. Another option would be to patch only the affected TestCase classes. Or maybe to silence E_USER_DEPRECATED notices within the test methods.

[acoulton]

@enov no, it was just I hadn't seen it :)

It's not the most beautiful thing, but I think it makes sense. Only patching the affected testcases would mean duplication, and having to patch others if we wanted to add assertTag before we add phpunit-dom-assertions.

Silencing E_USER_DEPRECATED is also an option, but would mean having to change and restore error reporting/handling every time - and we can't use try...finally in 3.3 so that would be just as messy if not more.

I think this workaround is as OK as it can be.

[enov]

Exactly, I'll open an issue as a reminder to fix things with phpunit-dom-assertions once it is released.