Trying to spec toString method
Added custom helper for vertex_specs
Added spec helper for edge.getType()
Replaced all instances of inDegree and outDegree with helpers
Added spec helpers for addEdgeTo, getOutgoingEdge and getIncomingEdge methods
Added helpers for removeEdgeTo, removeAllIncomingEdges, removeAllOutgoingEdges and removeAllEdges methods of Vertex
Added helpers for getting source and destination data
Fixed vertex.toString specs for the case where the vertex has more than one outgoing or incoming edges
Merge pull request #904 from prathamesh-sonpatki/custom_helpers

Custom spec helpers for IR specs related to Vertex.java