Add revision marking, changes/labels, MSG window

1. Support to mark good/bad revision.
2. Support switching between changes and labels.
3. Add the message window

Signed-off-by: hwangcc <hwangcc@csie.nctu.edu.tw>
Display p4 sync messages and fix some bugs

1. Redirect p4api error messages to the message window
2. Fix cursor moving
3. Sync code at init
4. Add the nosync option

Signed-off-by: hwangcc <hwangcc@csie.nctu.edu.tw>