Myriad fixes & cleanups in DeskClock.

Myriad fixes & cleanups in DeskClock.

 - Force the weather widget to actually fetch new data at
   the moment the device is docked, or when the screensaver
   disappears (if the device is plugged in).
 - Use Intent.FLAG_ACTIVITY_CLEAR_TOP to launch weather,
   music, and gallery to avoid jumping into the middle of
   their task stacks (http://b/2267831)
 - Fix layout issues with weather, particularly when the
   Genie widget is unavailable. (relates to
   http://b/2254472)
 - Internationalize the error message shown when Genie
   malfunctions.
 - Clean up weather & time displays to match UX specs more
   closely (fonts, shadow crop issues).
 - Remove some tabs in XML.
 - Internal cleanup: use "query" in the name of functions &
   variables related to getting updated weather from Genie;
   use "fetch" to refer to downloading new weather data from
   the network