Attempt to conserve battery life
Stupidly, I had neglected to STOP polling the accelerometer once the
screen was locked. Which made it drain battery *really* quickly.

Turns out the Android API is broken and won't stop polling the
accelerometer no matter what, even if you call unregisterListener(). The
receiver will just keep receiving legit samples and calling your receiver
method, even after you set everything to null. And battery still drains
a LOT.

Gr.
Merge branch 'master' of https://github.com/SyntaxBlitz/PluckLock

Conflicts:
	src/net/syntaxblitz/plucklock/AccelerometerService.java