Buddylist changes: remove bytes sent/received and userId, show giving/sharing icons, code cleanup

Changes for https://github.com/uProxy/uproxy/issues/622 (Better display of active buddies)

* Remove bytes sent/received
* Remove userId
* Show giving/sharing icons next to the user name
* Code cleanup:
 * Making variables private in ui.ts where possible
 * Moving more UI logic into startGettingInUiAndConfig and stopGettingInUiAndConfig, rather than having multiple UI update methods that need to be called.
 * Now mapping in the UI from instanceId to user, rather than instanceId to userName

Tested in Chrome, Firefox (UI loads), updated grunt test
why is this on-mousedown and not click or on-mouseup?  normal interaction of actually acting on a button doesn't happen until finishing the click.