Remove outdated TortoiseMerge doc sections

Based on TortoiseSVN revision 24199

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Don't ask whether to mark a file as resolved if we're saving before doing that anyway

Based on TortoiseSVN revision 24194

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Use a different icon for "enable edit": the previous one looked as if it was disabled, at least I always got confused

Based on TortoiseSVN revision 24202

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