Add client side request decoding tools

The request decoder is contained in the module "combo/dojo/requestDecoder".  To decode a request on the client:
* Load the decoder if not already loaded.  In the javascript debugger console, enter the command
```require(["combo/dojo/requestDecoder"], function(decoder){window.requestDecoder = decoder;})```
* Invoke the decoder specifying the URL you want to decode.  In the javascript debugger console, enter the command
```requestDecoder.decode("<paste URL here>");```.  The entire aggregator request URL may be specified.  The decoder will parse the query-args from the URL and decode the request and the object returned will contain properties listing the requested modules, scripts, deps and preloads specified in the request, as well as any features specified in the request.