* Add ip-api.com (ip lookup) support

This service returns better coordinates for Europe than other free ip lookup services available in geocoder.

* Clean the results class

Remove default responses for fields.

* Remove checking fields in url query

API already handles unknown fields, so this check is unnecessary.

* Add a test for using parameters directly in search method

No longer needed now that :yahoo lookup is gone.

I uncovered a small issue when switching from Yahoo BOSS to Google (with API, which requires enabling :use_https).  Because the Freegeoip.rb file is missing a supported_protocols method, it attempts to do an https lookup for IP lookups when enabling :use_https.

I already tested this on my setup and it appears to resolve the issue, with lookups/base.rb detecting that https is not supported for Freegeoip

TimeoutError is deprecated in Ruby 2.3.0. It has been an alias for
Timeout::Error starting in Ruby 1.8.0, and should be safe to replace.

The Yahoo BOSS Placefinder API is being discontinued.

https://developer.yahoo.com/boss/placefinder/

https://developer.yahoo.com/boss/placefinder/

the Yahoo lookup will be fully removed via:
https://github.com/alexreisner/geocoder/pull/985

I just spent a few hours trying to get this function to work, then realized I had my parameters in the wrong order. I was following the order listed in the comment, rather than the actual method definition! *facepalm* Anyhow, this fixes the comment, for the next person to read it.

This reverts commit 97b6bb94.