Culprits: .present? and .try

Appears to be defunct.

Fixes #609. Bing seems to support this type of character escaping now.
It's not discussed in their documentation but it works with every query
I've tried so hopefully we're finally good on this issue.

Also remove some unnecessary assertions from tests.

No longer seems to exist.

Fixes #1299.

and remove separate #latitutde and #longitude methods (which are defined
in base Result class).

* Update initializer template to use ipinfo_io

* Implement ipstack lookup

* Add Ipstack readme documentation

* Add post-install message

* Remove DSL from ipstack lookup

* Remove unnecessary logging

* Update post-install message

Fixes #1286.

Freegeoip/IPstack no longer provides keyless service.

Update Geocodio to v1.3

Fixes #1273.

some google geocoding requests have bounds within the result.  add a
helper to extract these.

* Add tests to cover results with no bounds

In this case, calling .bounds should return nil.  Oddly, calling
viewport on a result with no viewport causes the current code to `fail`.
I have preserved this behavior even though I think it to be a little
odd.

but default to HTTPS (custom hosts may not support HTTPS).
This partially reverts 7cb0acc9.

Rails 5.2 changed the receiver within a scope from `klass` to
`relation`. With that, we no longer have private access to
Geocoder::Store::ActiveRecord#near_scope_options, and so must make it
public.

see: https://github.com/rails/rails/pull/29301

Should have been part of 7cb0acc9

HTTP support will be discontinued according to this:
https://lists.openstreetmap.org/pipermail/geocoding/2018-January/001918.html

Fixes #1267

for Google Premier. No longer required, according to this page:
https://developers.google.com/maps/premium/overview

Fixes #1268

suggested by @alexreisner

Bing returns the status codes within the json response. When a request is
forbidden, it will return a 403. If there is an internal server error,
it will return a 500. And if the service is unavailable for some other
reason, it will return a 503. That information was obtained from bing's
[Status Codes and Error
Handling](https://msdn.microsoft.com/en-us/library/ff701703.aspx)
documentation.

We handle those three status codes here to raise
`Geocoder::RequestDenied` (for 403) and `Geocoder::ServiceUnavailable`
(for 500 and 503). This allows for the users of the Geocoder to handle
those errors in their applications.