Implement beginning of Shuttle Tracker

- Implement ShuttlesFragment: currently only draws an empty Google Map
- Implement WeatherFragment icon graphics: correct the WeatherHttpClient
class implementation to download items in the proper manner so that it
actually works
- Privatize class variables in package edu.rpi.rpimobile.model:
implement getters and setters
- Add newly created ic_wm_shuttle icons
Merge pull request #12 from pdpiech/release

Implement beginning of Shuttle Tracker