Fix bug 2068 and do some cleanup

Fix bug 2068 and do some cleanup

	* src/CutAndPaste.C (setSelectionRange, replaceWord): remove.
	(replaceSelectionWithString): select the new string after
	replacement; add a bool parameter indicating in which sense the
	selection is made.

	* src/lyxfind.C (replace): adapt to above changes.
	(find): comment out debug message.

	* src/frontends/controllers/ControlSpellchecker.C (isLetter):
	rename parameter.
	(nextWord): take a LCursor as parameter; set the selection over
	the word that has been found.
	(check): adapt to changes above (the length of the word is not
	necessarily the length of the selection -- fixes bug 2068).
	(replace): use cap::replaceSelectionWithString

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@14708 a592a061-630c-0410-9148-cb99ea01b6c8