This converts the client and weldrcheck functions to use http.Client for
connections instead of passing around the socket path and opening it for
each test.
This package will contain functions for communicating with the API that
can be used in both the integration tests as well as in a future cmdline
tool similar to composer-cli
When possible the client functions will return the same structures used
by weldr/api.go which have been exported in weldr/json.go
