Now it is necessary to specify which service is being used:
  Geocoder.configure(:maxmind => {:service => ...})
where '...' is one of: < :country | :city | :city_isp_org | :omni >

Now every fake query does not need to be listed in the code, a fixture
just needs to be added.

Changed since pull request was submitted.

Make Geocoder.configure accept a hash (now preferred) and add
Geocoder.config method (for reading config). Deprecate old syntax.

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

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

previously the mapquest service was relying on an outdated url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

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

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

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

For consistency with rest of code.

This has always been the intended behavior (as shown by the README's
sample code which begins `if results.first`) but it wasn't implemented
properly. Thanks to github.com/nhippenmeyer for pointing it out.

Removed set_defaults from all tests and replaced with teardown to reset the defaults.

Signed-off-by: James McCarthy <james2mccarthy@gmail.com>

Allows custom handling of geocoding service connection problems.