Asynchronous project loading spinner now disappears when finished.
Merge branch 'master' into ben_audiofeedback

Conflicts:
	CollectorAndroid/src/uk/ac/ucl/excites/sapelli/collector/load/AndroidProjectLoaderStorer.java
Prevent NullPointerException on Field.hashCode and Field.equals
Audio feedback seems to be more or less working (not tested on modes
other than SEQUENTIAL yet).