Fix regressions in Fold and Up commands
Fix regressions in Fold and Up commands

• Fold must redefine self.index when folding many regions at once;
• Up puts cursor onto correct disk on Windows instead of first one

altairn5/SublimeFileBrowser,meganlkm/SublimeFileBrowser,breunigs/SublimeFileBrowser,aziz/SublimeFileBrowser,mrvkino/SublimeFileBrowser,breunigs/SublimeFileBrowser,mrvkino/SublimeFileBrowser,altairn5/SublimeFileBrowser