admin: fixed "returns" links to sale/customer/edit in Dashboard recent a...

admin: fixed "returns" links to sale/customer/edit in Dashboard recent activity comments (there was wrong order of serialized activity data)
admin: added "returns" links to sale/return/edit in Dashboard recent activity comments
screenshot before this commit: http://prntscr.com/4utv2d
screenshot after this commit: http://prntscr.com/4utval