Merge pull request #1635 from bas-vk/useragent

cmd/geth/js.go

cmd/geth/main.go

cmd/utils/flags.go

rpc/api/admin.go

rpc/api/net.go

rpc/api/personal.go

rpc/api/personal_args.go

rpc/api/shh_js.go

rpc/codec/codec.go

rpc/codec/json.go

rpc/comms/comms.go

rpc/comms/inproc.go

rpc/comms/ipc.go

rpc/comms/ipc_unix.go

rpc/comms/ipc_windows.go

rpc/jeth.go

rpc/useragent/agent.go

rpc/useragent/remote_frontend.go

xeth/xeth.go