we try to use the geoip service, and if the answer has an entry for the
sorted gateways, we just use it instead of using the timezone heuristic.

- Resolves: #84

Get local timezone and http client as configurable things in bonafide,
so tests can set them. Also separate integration tests and unit tests.

it turns out that "full path" is still a relative path, and therefore
not allowed as a GOPATH.

- Resolves: #75