Added first run tooltips, visual improvements
-added rounded sidebar image
-replaced vibration icon with slightly larger version

ChromeHelpPopup:
-tooltip something like the chrome first run tooltips

MainActivity:
-tooltips are shown on first run (add event, and quicksilence button) or when there are no events (add event) or when no calendars have been selected to be synced (settings button)
-added broadcast receiver to be notified when one tooltip is dismissed (so that all tooltips can be dismissed together)

ShowUpdatesActivity:
-updates dialog is only shown if not on first run

TooltipManager:
-added manager to simplify sending broadcasts when a tooltip has been dismissed

Prefs:
-added methods to get and set first run status