bug: uncapitalized service name causes runtime error unknown function in service.pb.gw.go

[thurt]

see title.

Steps to reproduce:

1. define a service with a name that has a lowercase first letter in your service.proto
2. generate the service.pb.go (notice that the generated code includes func NewNameClient -- it is capitalized Name)
3. generate the service.pb.gw.go (notice that the generated code attempts to call NewnameClient -- uncapitalized name which leads to the runtime error)

this looks similar to #300 and looks like it could be fixed in the same way.

the style guide, https://developers.google.com/protocol-buffers/docs/style, says you should capitalize service names, but seems it does not say it requires capitalized. So i think this is a valid bug

[achew22]

I think you're totally correct. This would be a nice contribution for a first timer. I'll even point you to the appropriate code if you want 😉