Yandex API key is not required

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.

Also add test for method presence in all lookups.

This code appears to be copied from the Freegeoip lookup, where it is
undesirable to begin with.

Conflicts:
	test/lookup_test.rb

Conflicts:
	README.rdoc
	lib/geocoder.rb
	lib/geocoder/configuration.rb

Fix query params escaping for OauthUtil

Conflicts:
	lib/geocoder/query.rb

Conflicts:
	lib/geocoder/query.rb

Cache is now lookup-specific.

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

instead of instance variables.

Previously they were testing many things which were not configuration.
All we care about is whether settings are read/writeable via the methods
provided.

Conflicts:
	lib/geocoder/lookups/base.rb
	lib/geocoder/lookups/yahoo.rb
	lib/geocoder/query.rb