This requires changing the way stubs work, so that they only simulate
actual HTTP calls, not cache hits.

Also move API key config to separate method.

Allow lookups to define a cache key (defaults to the query URL) and
define Yahoo's as the non-OAuth-encoded request URL.

Add test and display Yahoo's error message in warning.

This addresses:
https://github.com/alexreisner/geocoder/issues/322

previously the mapquest service was relying on an outdated url
that was just defering to the Nominatum service. This commit
brings in supported Mapquest API support for v1 of their API.

It supports the open (free) tier of the API along with the
licensed version of the service.

Auto-detect which one is being used. It's necessary to continue
supporting 1.0 because of the existing data in people's caches.
See discussion: http://github.com/alexreisner/geocoder/pull/307

Need to be testing that it works without additional requires.

"Results" key is now "Result" and is not an array when only one result.
Update code and response fixtures to reflect this.

"Results" key is now "Result" and is not an array when only one result.

Fixes: #194 - add_exclude_condition breaks on tables without ID field - https://github.com/alexreisner/geocoder/issues/194

in request to geocoding service.

Also move some lookup-related methods to Geocoder::Lookup module.

This is in preparation for adding Maxmind as an IP lookup.

This fixes issue #244.

This requires a parameter to be accepted by the block passed to
Geocoder.configure, which means you don't need to remember that the
method is called "config"--you can call it whatever you want.
This behavior seems more standard for configuration blocks.

methods to avoid creating an index by default.

Geocoder.coordinates sometimes returns nil which causes crashes in the distance
and bearing calculations. By returning a point array of [ NaN, NaN ] this
distances will be also NaN which seems to be a sensible result. If the argument
to extract_coordinates has an unexpected form, also return [ NaN, NaN ].

It's not an ideal name either, but it's short and it's slightly more
specific than "method".