Fix setter so IE7/8 can set text of style element

fixes #2265

Our setters brake old IE when setting text of a style element.
This pull request adds a alternative `propertySetters.text` in case the problem exists in the Browser.

Used some ideas from @arian's  fix on his `fix-2265-text branch`.
@ibolmo good point. Commented this with @arian also and I changed in [html setter for style](https://github.com/SergioCrisostomo/mootools-core/blob/fix-2265-ieStyleText/Source/Element/Element.js#L1069), to point here since we would need less code that way. 

Updated, re-tested and rebased.