Merged in feature/tracker_service (pull request #6)

all right
add push notification messages
add date serilizer
add date serilizer
improve logging
fix GCM category
device data collection updates
rough implementation of registering GCM service
add rough push
commit
add message type deserializer
Merge branches 'feature/push-notification' and 'master' of https://github.com/iveyalkin/device-radar

Conflicts:
	app/src/main/java/org/bitbucket/rocketracoons/deviceradar/network/ApiClient.java
	app/src/main/java/org/bitbucket/rocketracoons/deviceradar/screen/MainActivity.java
	app/src/main/java/org/bitbucket/rocketracoons/deviceradar/service/TrackerService.java
	app/src/main/java/org/bitbucket/rocketracoons/deviceradar/utility/Constants.java
data collector updates
Merge branch 'master' into pavel/development
fix merge issue; re-factor shared prefs
Merge branch 'pavel/development' of https://github.com/iveyalkin/device-radar
add real guid
fix typo
Merge branches 'feature/tracker_service' and 'master' of https://github.com/iveyalkin/device-radar into feature/tracker_service

Conflicts:
	app/src/main/java/org/bitbucket/rocketracoons/deviceradar/network/ApiClient.java