refs # 8348

Added functionality for querying all service instances for particular values. Also added tile service instance independent request services for pulling tile data without it being stored and managed by a particular instance.
Take a look at [lodash](www.lodash.com) - it has helpers to hide lot of the ugliness associated with objects as maps in JS.  There's a [forEeach](https://lodash.com/docs#forEach) that's worth the effort of integrating the library alone.  If you want to put your Scala experience to work it has a reasonable set of combinators defined in it too.