* Painter.h:

* Painter.h:
  * Painter: new ctor that sets drawing_enabled_ to true.
  * setDrawingEnabled(), isDrawingEnabled(): new methods.

* QLPainter.C: only draw if drawing is enabled.

* nullpainter.h: deleted.

* rawpainter.C::paintPar(): only draw if we are inside the Paragraph.

* InsetTabular::draw(): use new Painter method instead of a NullPainter.

* InsetMathNest::drawSelection(): ditto.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@15613 a592a061-630c-0410-9148-cb99ea01b6c8