Use more CGit::CombinePath() to refactor code

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Add ad-hoc tab mode combobox in ribbon status bar

Based on TortoiseSVN revision 25628

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Add Use Spaces and Smart tab char in Settings page

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Drop Use Spaces and Smart tab char from ribbon toolbar

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>