Add set language interface into all the services.

[LornTao]

@zugaldia
In order to set a default language when customize the map out of the English language areas. Optimization, Map Matching, and Directions also should support a language parameter. We should do the same for these services as Geocoding Service here.

cc/ @cammace

[cammace]

I've added language support for the Directions API (see #504) and Optimization API (see #506). I'll continue adding more language options to the other APIs as I go through updating them.

[cammace]

Finished adding all language params in #507 for all APIs. Will be available in MAS 2.2.0 release