Add abstract RouteService class

The RouteService class is meant as a base class for
route service classes.
Add EPAF decoder

Add a decoder for Encoded Polyline Algorithm Format (EPAF).

EPAF is a Google format for space efficient serialization of
coordinate series. Both OSRM and GraphHopper uses it for encoding
their routes.
Utils: add isArray-function

Utils.isArray checks if an object is an array. This isn't very
straight forward in JavaScript unfortunately so best to make a
separate function for it.

More information:
 - http://blog.niftysnippets.org/2010/09/say-what.html
 - http://stackoverflow.com/questions/4775722/javascript-check-if-object-is-array
Utils: add isDefined function.

Utils.isDefined returns true if a value isn't undefined or null.
HTTP: add a HTTP helper module

Http.Query is a class for easy construction of HTTP query-lines,
that is the part after '?' and before '#' in an HTTP URL.
RouteService: Add GraphHopper support

Add support for routing via GraphHopper HTTP REST interface.