Previously the richedit control contents were scrolled directly using
ScrollWindow.  This caused the richedit control to not actually scroll,
but only look like it scrolled, therefore causing plenty of glitches.

That still leaves IWineD3DIndexBuffer, but that code is also mostly similar,
except for the conversion code (which will be unused there).

The documentation for TxNotify says that it is not called with the
EN_MSGFILTER notification, so I made sure ME_FilterEvent didn't call
this method.

sane.ds: More correctly detect an end of scan job from sane; this enables Acrobat to pull multiple pages in one scan.