Android: Fix and enable input device sensor input

This reverts commit 75fb1a7edfb12f490b08ab0b76a8e2f1536d2d9b.

To fix the crash in input device sensor handling, we should look up
Sensors using structural equality. Unfortunately, Sensor.equals
implements referential equality, and HashMap doesn't let us provide a
custom comparator. Because the number of sensors is relatively small,
and because we have a reason to keep a sorted list of sensors around
anyway, let's switch from HashMap to ArrayList.

Handle Pausing in AchievementManager

This reverts commit 72cf2bdb87f09deff22e1085de3290126aa4ad05.

SYSCONF settings are getting cleared when they shouldn't be. Let's
revert the change until I get proper time to figure out why it's broken.