Add ad-hoc tab mode combobox in ribbon status bar

Based on TortoiseSVN revision 25628

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Move default Use spaces and Smart tab char from ribbon to Settings page

Based on TortoiseSVN revision 25629, 25630

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Update libgit2

Need this to fix issue #2017

Signed-off-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>
Extend first argument of CGit::GetOneFile() to handle with blob refname

Signed-off-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>
Add GetOneFileCommand

Signed-off-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>
Use command "getonefile" to get Versioned file, instead of "cat" command

Signed-off-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>