revamped check-in experience, fixes #24, now it's possible to implement #73 and #13
Merge branch 'master' into 27-Check-In-With-Friends

Conflicts:
	code/Glasquare/src/main/java/cz/destil/glasquare/activity/CheckInActivity.java
	code/Glasquare/src/main/java/cz/destil/glasquare/api/CheckIns.java
	code/Glasquare/src/main/res/values/strings.xml