Add Cucumber support for VertexProperty for language bindings

We have Cucumber support for VertexProperty now in Java, so we need to add similar support for the three language bindings. Currently there is only one feature test that uses the VP feature, and it is disabled in the langs. We reused the edge triplet syntax:

vp[vertexName-propName->propVal]

Note that propVal must also be parsed (e.g. numerics):

vp[peter-age->d[35].i]