Add geolocation browser API module

Handle geolocation feature-detection with Modernizr. Throw error when browser doesn't support it.
Add Google Maps JavaScript SDK
Change `#getLocation()` to `#getCoordinates()`
Convert browser location to readable string

Use Google Maps to geocode browser geolocation API's latitude and longitude.
Add location extract function

Extract given data from Google Maps geocode response. Support only `city` and `country` for now.

Example: `geomancer.extract(location, 'city', 'country')`
Fix `Index#init()` not being a function
Detect user location in registration form
Merge branch 'geolocation'

* geolocation:
  Detect user location in registration form
  Fix `Index#init()` not being a function
  Add location extract function
  Convert browser location to readable string
  Change `#getLocation()` to `#getCoordinates()`
  Add Google Maps JavaScript SDK
  Add geolocation browser API module

Close #4.