Implement proximity sensing for GPS update

Improved semaphore usage
Implement proximity sensing
Code cleanup
Update README
Implement GPS signal acquisition timeout
Merge branch 'AJS_gps_timeout' into AJS_add_proximity_sensing
Ensure latest relavant location is used for issuing updates
Remove gps timeout callback on service destroy
Use android provided proximity alerts

Use custom workaround for immediate location update on updating
requestLocationUpdates parameters
Update alert dialog
Merge branch 'AJS_gps_proximity_method_2' into AJS_dev

Conflicts:
	src/com/kab/wherefi/service/DataService.java