Fixes #1299.

* 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

Freegeoip/IPstack no longer provides keyless service.

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.

This reverts commit 385aafa0.

Should have been part of 7cb0acc9

See https://github.com/ruby/ruby/commit/e1b432754553423008a14d39d0901eabc99e7ddb

see: https://github.com/alexreisner/geocoder/pull/1254#issuecomment-359118927

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.

Remove silly check for HTML tags
Add test case for invalid json

* Handle Geocoder::OverQueryLimitError gracefully.

Geocoder::OverQueryLimitError errors were not being generated correctly, and the response was coming back empty but with no indication.

This changes the behavior slightly so that unknown errors are also returned.

* Add error handling tests

* Remove unnecessary config in tests

* Add support for DB-IP.com geocoding service

* Added support for https with paid accounts

* Use `use_https` to distinguish between paid/unpaid API usage

* Clean rubocop warnings

* Update LocationIQ geocoding provider with limits and handle errors

* Correct syntax errors

* Update over limit fixture

* Set HTTPS as the assertion for the URL

* Add missing fixtures for unit tests

* Correct the mistakes in doc

* Let users decide SSL usage

* Revert incorrectly asserted URL without https

* Remove use_ssl from lookup subclass

* Update the assertion of the URL to HTTP and not HTTPS

* Allows radius to be a symbol representing a column in DB

* Proposed changes by @alexreisner:

- Keeping branching condition consistent
- Not overwrite the method argument: ‘radius’
- Not assigning two variables in a single line, and
- Add code comments where needed

By “proposed” I meant, I copy/paste them from his comment. But we are
in agreement.

* Fixes broken test in PR

* Added support for AMap, aka AutoNavi Map, 高德地图

* Try to include amap error info if failed

* Get correct result from amap response

* Fix result error in amap return

* Refactor codes for AMap handling

* Refactor codes for amap result handling

* Refactor amap handling codes

* Fixed coordinates handling error

* Added tests

* Fixded amap result handling and tests

* Lock webmock on 2.3.2 for ruby 1.9.3 support

Maxmind geoip2 returns a collection of names in all available languages
for each field.
This commit allows us to change the language of a single result without
having to reconfigure Geocoder.

* Create methods removing port from ip addresses; Add test

* Update geocoder_reject_non_ipv4_addresses; Add more tests

Update smarty streets results coordinates method to return nil when both latitude and longitude do not exist