Minor: refactoring of VertexIdType. Fixed "if-else polymorphism" anti-pattern.
Minor: refactoring of VertexIdType. Removed unnecessary implementation of getVertexCache in parent
Merge pull request #448 from orientechnologies/vertexIDTypeRefactoring

Minor: refactoring of VertexIdType.
Fixed issue #449
Removed warning if setWarnOnForceClosingTx(false)
Merge branch 'master' of https://github.com/orientechnologies/blueprints