Revert "Add support for <blockquote> elements"

Whoops, merged too soon. The dropdown part of it doesn't
actually work right.

This reverts commit 3c51ebad93480c4f52215c83859e8022b7103cf5.

Change-Id: Ieafbf18ca8a43b07e33a787772abbc77aef63e4c
Merge "Revert "Add support for <blockquote> elements""