If update check failed, delete the cache

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Fixed issue #1975: Pull Dialog should remember fast forward only

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
TortoiseGitMerge: If the target text can only be found in one line, do not say not found when end of line is reached

Based on TortoiseSVN revision 24934

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
TortoiseGitMerge: Add Search Up direction

Based on TortoiseSVN revision 24935, 24936

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