Backport to Android 2.1

[nicolas-raoul]

By Alex:

I think it'd be cool if Wikivoyage would work on devices running Android
2.1; an example would be the Nook Simple Touch.

I've actually used apktool to build myself an apk with
android:minSdkVersion="7" and it seems to work. The only problem I've
noticed is that after a few clicks, it doesn't load further pages (e.g.
Europe->United Kingdom->England->Bristol changes the title bar, but doesn't
load)