CHANGELOG update
Merged r2766 and r2783 from trunk.
Merged r2722, r2771, r2772 from trunk.
Merged r2768, r2773, r2774, r2775, r2796 from trunk.
Merged r2797, r2804, r2814, r2820, r2837, r2838 from trunk.
Translation updates * Korean (#3855) * Russian * Traditional Chinese (#3853)
Fixes group update form url (#3854).
Slight change to the visibility SQL statement.
Adds spent time to the activity view (#3809).
Fixes Textile reference link (#3812).
