Volley images

Add support for using Volley to load remote images instead of UIL

1. Gives us Caching
2. Load images at full resolution, rather than hardcode them. This is done by trying to fetch an image at highest width possible for the particular view. If it 500s, we assume that the image is smaller than the requested width and just request the full size image
3. Created a MediaWikiImageView, to which you can pass a Media object and it will display it. Takes care of sizing, etc. Optionally you can also specify a view to use as the 'loading' view.

TODO:
Loading from content:// URIs still use UIL. Need to write a Volley HTTP Stack that can fake responses for content:// URIs.

GitHub: https://github.com/wikimedia/apps-android-commons/pull/1
Change-Id: Ia21a7b19fefa552d5a0b013085d0f5f1f80dc5ff
Upgrade Maven Android plugin to 3.6.0

Makes it work with newer version of Android SDK

Change-Id: Id84e91720f2a08f6529334ca111dc197bc61adc1
GitHub: https://github.com/wikimedia/apps-android-commons/pull/2
Clean out some excess logging

Change-Id: I3207086bae63f077c5808fba10e9fec9931ab4f1
GitHub: https://github.com/wikimedia/apps-android-commons/pull/3
Do not batch responses from image loader threads

Don't wait to batch image loads, just send 'em back as fast as
possible

Change-Id: I4a97d938c38157d4b534580a037fa950c89b1de9
GitHub: https://github.com/wikimedia/apps-android-commons/pull/4
Add subtle way to show people where uploads are going to

Says 'testwiki' or 'commonswiki' at the bottom of About

Change-Id: I757bb5820985e950476e1c9b4d274e35dfcc7b96
GitHub: https://github.com/wikimedia/apps-android-commons/pull/5