Minor refactoring

Based on TortoiseSVN revision 25959

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Optimize log context menu order

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Fixed issue #2327: Help button is broken in "SVN Commit Type" dialog

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Drop unused variable

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Check file size before checking content

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Refresh the status of "Working dir changes" after click it

Signed-off-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>
Take a break and more TRACE

Attach to process succeed, but can't use break point. -_-!
so, adding some debug strings.

Note a issue: (suppose it is not related to this change, but note it.)
git.exe spends few minutes to finish its work.
Since it does not response, the ReadFile() blocks AsyncDiffThread().
And git.exe seems end up with some error (ReadFile() return FALSE)