enh: start adding new text/annotation framework. Old cache disappears, Freetype internal cache framework is used instead. Text used to be rendered using glPixmap/glBitmap in 2D, it will now be rendered in a buffer and used as a text on a quad, to allow arbitratry placement in 3D (later on, outline will be extrauded for true 3D). Also add support for orientation. Experimental for now, vtkTextActor is unchanged, vtkTextActor2D and vtkTextActor3D will be used to test new feature until transition is done.