* BufferView_pimpl.C:

	* BufferView_pimpl.C:
	* lyxtext.h:
	* text.C:
	* text2.C:
	* text3.C:
	* undo_funcs.[Ch]: use paroffset_type instead of
	  ParagraphList::iterators to prevent multiple conversion
	  (and get a more robust interface)

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@7909 a592a061-630c-0410-9148-cb99ea01b6c8