Catch regex exception

Based on TortoiseSVN revision 25330

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
TortoiseGitMerge: Check valid regular expression in Regex Filter Dialog

Based on TortoiseSVN revision 25329

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Show regex error messge in AutoTextTestDlg

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