* Allows radius to be a symbol representing a column in DB

* Proposed changes by @alexreisner:

- Keeping branching condition consistent
- Not overwrite the method argument: ‘radius’
- Not assigning two variables in a single line, and
- Add code comments where needed

By “proposed” I meant, I copy/paste them from his comment. But we are
in agreement.

* Fixes broken test in PR

specify rails version for migrations

Add time_zone to Opencagedata result

for clarity (damn, the README has gotten awfully long).

Reverting back to freegeoip.net (from freegeoip.io) as
it appears to be the intended default host (see:
https://github.com/fiorix/freegeoip/issues/165).

Source: http://freegeoip.net/

* Add place_id search for Google search

* Add place_id example to wiki

* Update README.md

* fix

Link to configuration.rb in docs

Add source code and changelog links to gemspec

add support for abbrv param

OpenCage recently added a new optional parameter "abbrv".
Some details: http://blog.opencagedata.com/post/160294347883/shrtr-pls

Add `:params` for geocoded_by and reverse_geocoded_by

add connreset to network errors

Change documentation about pelias

It seems that pelias section had the same links as mapzen. Changed that so that it points to pelias github page.

Allow to limit the objects that will be geocoded by rake task

add ip_lookup option to initializer template

I noticed this option was in the README, but not in the template, so it
might be nice to have it generated in the template as well.

return state_code instead of alias state

Current webmock is not compatible w/ Ruby <2.0.