Add CInputBox class

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
TortoiseGitProc sendmail command supports to, cc, subject command line arguments

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Input comment message and call TortoiseGitProc to sendmail

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