Refactors tests for default values.
Handles NumberFormatException produced by non-integer strings.
Adds testing workaround for hex default values.
Lint is broken in latest version of tools. Disabling until fixed.

https://code.google.com/p/android/issues/detail?id=72596
Merge pull request #213 from mapzen/chuck/handle-exceptions-in-edit-int-prefs

Edit int prefs
WIP