Expose method name in tchannel.CurrentCall

[prashantv]

This is a little trickier than the others, since normally we just return the same *InboundCall object which satisfies the interface.

The *InboundCall object exposes method as Method() []byte and MethodString() string (for performance reasons).

If we wanted to reuse the *InboundCall object, we'd have to expose the methods as one of the above which seems a little hacky. Ideally we just expose Method() string, but this will require some internal refactoring, especially since we'll want to do this in a backwards compatible way.