To tell the widget where it gets its data from, one has to invoke
init({ menuUrl: 'http://url-to-menu' }) from js.

This will reduce the size of the json and avoid flashing on update.

We save the async fetched json data to shared preferences and
invoke notifyAppWidgetViewDataChanged when it changes.

Use StringBuilder in loop for better performance and ensure resources are recovered regardless of any problems that may occur

add NEW_TASK flags when start settingsActivity

#9 #1707

load saved info when settingsActivity is reloading

retry geoInfo when fail to get geoInfo

#1658

retry geoInfo after 1min.

#1707

add settgins, update button on widget

reorganize views for resizing icons

#1707
add vector icons
show aqi value on aqi widget
remove protected setWidgetStyle
modify update time to download time
display "loading"msg at update is started.