* Changes backported from FLOW3:
  * major cleanup and refactoring of core and view helper classes & comments
  * added validation for boolean arguments in AbstractViewHelper
  * added initialize-method to AbstractViewHelper, that is called before render(). This was especially needed for tagbased viewhelpers.
  * renderChildren() now directly calls evaluateChildNodes() on the respective view helper node allowing us to render objects/arrays.
  * improved boolean type conversion for arguments in ViewHelperNode.
  * added TagBuilder class, re-wrote all tag based view helpers to use it (see form view helpers for some examples)
  * ViewHelperArguments collection got a new method "hasArgument()" that returns TRUE when the specified argument exists and is not NULL
* tx_fluid changes:
  * Improved fake object factory. Now objects are injected to subclasses and implementations of the specified classes/interfaces.
  * cleaned up and tweaked view helpers. Removed Parsefunc, Stdwrap and TypoScript view helpers for now. Added CObject, If/Then/Else, EmailLink, Crop, Currency, Debug, HTML, Nl2br, Image view helpers. Thanks to Sebastian Böttger, Christopher Hlubek, Niels Pardon, Andreas Pattynama for the help! 
* Note: Unit tests not fully backported yet.