Added async_storage.js

-This is the Mozilla recommended way of doing simple localStorage calls for priveleged apps.
-Async Storage is asynchronous, and will not block the main thread, whereas localStorage will
Added Settings form and processing

-Added a simple settings form with two fields, temperature threshold, and weather tolerance
-Temperature threshold is the lowest temperature a user is willing to hike in
-Weather tolerance is the overall tolerance a user has for inclement weather
-All field data is saved locally via the async_storage library