Create a now json format that (for example jsonm): minifies the output (strip extra whitespace and hard returns) and gzips it.

The current output of JSON API is rather fat in size. It averages ca 100 kb per request.

So it would be good if we either create a new json format like 'jsonm' or add another parameter that signifies that that the output should be compressed to reduce the file size.

So options are:

* strip surplus whitespace
* strip hard returns
* or, just gzip the output when you give it back to the browser.