methods to avoid creating an index by default.

Move to method-level rescue where appropriate

Avoid crashes during calculations. 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 ].

Add support for custom HTTP request headers

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 ].

This addresses issue #195.

Add support for cache stores with :get and :set methods.

Altered the Geocoder#ip_address? method to recognize IP addresses prefixed with ::ffff: as is common with webservers binding to ipv6 sockets

Should have been part of commit eba79f25.

Return zero results more reliably. Formerly an exception was raised when
the table didn't have an 'id' column.

This is to fix #187

Yandex service fix

In lookups/base, invalid JSON needs to be rescued for ActiveSupport::JSON

Fix for parse_raw_data -- json parse catches invalid json and activesupport::json needs to be caught.

Fix for: Issue #162

within_bounding_box scope takes field names from options