Merge tag '1.6.4' into develop

Release 1.6.4

Conflicts:
	build.xml
	client/pom.xml
	commons/pom.xml
	core/pom.xml
	core/src/main/java/com/orientechnologies/orient/core/OConstants.java
	core/src/main/java/com/orientechnologies/orient/core/cache/OAbstractMapCache.java
	distributed/pom.xml
	distribution/pom.xml
	enterprise/pom.xml
	graphdb/lib/blueprints-orient-graph-2.5.0-SNAPSHOT.jar
	graphdb/pom.xml
	graphdb/src/test/java/com/orientechnologies/orient/graph/blueprints/BlueprintsTest.java
	graphdb/src/test/resources/com/orientechnologies/orient/graph/gremlin/graphdb-test.xml
	history.txt
	nativeos/pom.xml
	object/pom.xml
	pom.xml
	server/pom.xml
	tests/pom.xml
	tools/pom.xml