Patch from Michele to make tab and backspace in indentation work better.
Patch from Michele to make tab and backspace in indentation work
better.

R1dO/scintilla_clone,R1dO/scintilla_clone,R1dO/scintilla_clone,R1dO/scintilla_clone,R1dO/scintilla_clone,R1dO/scintilla_clone,R1dO/scintilla_clone,R1dO/scintilla_clone