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.

Clean up Core::GetState

Some pieces of code are calling IsRunning because there's some
particular action that only makes sense when emulation is running, for
instance showing the state of the emulated CPU. IsRunning is appropriate
to use for this. Then there are pieces of code that are calling
IsRunning because there's some particular thing they must avoid doing
e.g. when the CPU thread is running or IOS is running. IsRunning isn't
quite appropriate for this. Such code should also be checking for the
states Starting and Stopping. Keep in mind that:

* When the state is Starting, the state can asynchronously change to
  Running at any time.
* When we try to stop the core, the state gets set to Stopping before we
  take any action to actually stop things.

This commit adds a new method Core::IsUninitialized, and changes all
callers of IsRunning and GetState that look to me like they should be
changed.

Regression from 5171290bdb.