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.

try-catch for ArrayIndexOutOfBoundsException, NullPointerException

rename apppreferences to widget_preferences

set requestCode for Classification

check null of geo info
update format of geoinfo.tostring

move alarmManager to WidgetProvider from Settings