Some adds for client management.
Improvements on client management.
Merge remote-tracking branch 'origin/master'

Conflicts:
	agendize-api/src/main/java/mx/agendize/api/APIUtils.java
	agendize-api/src/main/java/mx/agendize/api/scheduling/reference/AgendizeObjectHelper.java
	agendize-api/src/main/java/mx/agendize/api/scheduling/reference/Client.java
	agendize-api/src/main/java/mx/agendize/api/scheduling/reference/Picture.java
	agendize-api/src/main/java/mx/agendize/api/scheduling/v2/ClientsManager.java
	agendize-api/src/test/java/mx/agendize/api/scheduling/v2/ClientsTest.java