TRUNK-3963: Visit validator should prevent or allow overlapping of visits depending on global property

Conflicts:
	api/src/main/java/org/openmrs/util/OpenmrsConstants.java
	api/src/test/java/org/openmrs/api/db/PatientDAOTest.java
	api/src/test/java/org/openmrs/api/db/hibernate/PatientSearchCriteriaTest.java
	api/src/test/java/org/openmrs/util/GlobalPropertiesTestHelper.java

Fixing failing tests for: Visit validator should prevent or allow
overlapping of visits depending on global property - TRUNK-3963
Conflicts:
	api/src/test/java/org/openmrs/validator/VisitValidatorTest.java

Putting back commented out code at: Visit validator should prevent or
allow overlapping of visits depending on global property - TRUNK-3963
Conflicts:
	api/src/main/java/org/openmrs/util/OpenmrsConstants.java

TRUNK-3963: Missing messages added

TRUNK-3963: Visit validator should prevent or allow overlapping of visits depending on global property

Conflicts:
	api/src/main/java/org/openmrs/util/OpenmrsConstants.java
Merge pull request #1215 from pmuchowski/TRUNK-3963-1.9.x

TRUNK-3963: Visit validator should prevent or allow overlapping of visit...