Get, create, update, delete methods for all objects.
Use of enumerations for countries, languages, days of the week.
Better JUnit test cases.
Merge remote-tracking branch 'origin/master'

Conflicts:
	agendize-api/src/main/java/mx/agendize/api/scheduling/reference/WorkingHours.java
	agendize-api/src/main/java/mx/agendize/api/scheduling/v2/ClientsManager.java
	agendize-api/src/main/java/mx/agendize/api/scheduling/v2/CompaniesManager.java
	agendize-api/src/main/java/mx/agendize/api/scheduling/v2/SettingsManager.java
	agendize-api/src/main/java/mx/agendize/api/scheduling/v2/StaffsManager.java
	agendize-api/src/test/java/mx/agendize/api/scheduling/v2/ClientsTest.java
	agendize-api/src/test/java/mx/agendize/api/scheduling/v2/CompaniesTest.java
	agendize-api/src/test/java/mx/agendize/api/scheduling/v2/StaffsTest.java