Invalid method check for Page_Controller->data()

[Zauberfisch]

In ControllerTagGenerator.php#L22 we are adding the @method Page data() tag for the Page_Controller.
While doing so, we call $this->pushMethodTag($pageClassname, $pageClassname . ' data()'); which is actually an incorrect use of pushMethodTag().

pushMethodTag() takes a method name as first argument to check if this method already exists, since the method name is data(), we should pass data instead of $pageClassname.

This however reveals the next issue: data() does exist as method because the parent ContentController implements it. So this check would not yield the desired result either.

I believe the discussion if we modify pushMethodTag() to make this possible should take place in a separate issue.
Let's keep this issue open until we decided to proceed with pushMethodTag() and either fix it with 'data' or if it's not updated add a comment to explain why we are not using 'data' here.

[Firesphere]

This should be solved in #107, but if not, please re-open this issue?

Closing for now as #107 is expected to solve this issue.