Editor Utilities to LineDocumentUtils migration

[mbien]

Switched to non-deprecated editor utilities API.

PR is split into commits which usually handle a method pair.

note to first commit:

LineDocumentUtils unfortunately broke symmetry in getLine[Start/End]:

• getLineStart didn't declare BadLocationException to be thrown and did not have any range checks
• getRowStart declared BadLocationException but called getLineStart which can't throw the Exception

to resolve this I had to add getLine[Start/End]Offset and deprecate getLine[Start/End]:

• getLine[Start/End]Offset checks the range and declares BadLocationException, just like the getLineEnd sibling did.
• this makes the API symmetrical and allows the try-catch blocks (which had to be already implemented) to function

its ugly but this was the best option I came up with.

[mbien]

duplicated code strikes again

[mbien]

rebasing. planning to merge this this week assuming everything is ok.

[mbien]

fixed a few mistakes, will merge once green. then proceed with the maven update PR.