Display some pins for only a handful of closest spots

* Used the Google Geometry library to calculate the distance for
  each parking spot from the user current location
  [Geometry Library](https://developers.google.com/maps/documentation/javascript/reference?hl=en-US#spherical)
* Sort the collection of the locations by the smallest distance
* Take the ten closest and display a pin if it has a valid location name

Next steps:
* Make the pins clickable to display the option for directions
* Clean up the code
Merge pull request #9 from mknudsen01/keep-5-closest-spots

Display some pins for only a handful of closest spots