Themes: Handle processing themes in separate thread

If themes are being processed and the user attempts to apply a theme
they will be forced to wait for themes to finish processing before
the theme is applied.  This patch moves processing of theme resources
into a separate handler/thread.

Change-Id: Ib30a1be75915364c2867df04d63700be63c9f2c5
ProximitySensor: check for correct MaxRange value

Use TYPICAL_PROXIMITY_THRESHOLD for devices that returns incorrect mProximitySensor.getMaximumRange() value;

Presto's proximity sensor returns values: 0.0f(near) or 5.0f(far).
mProximitySensor.getMaximumRange() must return proximity sensor's availible range, but it always return 0, so mProximityThreshold is also 0.

So boolean positive = distance >= 0.0f && distance < mProximityThreshold;  positive will never be
true.
The cause of this problem is proprietary sensor.msm8660.so, it must set proper Range and Resolution for proximity sensor.

Change-Id: I0cf81fd20f210115cbd6db10c0070b12f1c57336