Add /posts tests for GeoJSON and JSONP formats
Improve JSON format error: provide more info about why it didn't parse.

* Uses json_last_error() to get json parsing errors
* Adds seperate check to ensure array/object JSON supplied
* Remove outer try/catch since json_decode() doesn't throw Exceptions
RestContext improvements

* Add test for JSONP
* Add test for response does NOT have a property
RestContext: Make typeOfPropertyIs() check flexible

* theTypeOfThePropertyIsNumeric() converted to theTypeOfThePropertyIs()
  with ability to add further type support
Allow checking deeply nested property types and values

* Using Arr::path() to get properties burried deeper in the JSON
  This allow checking properties like: 'values.last_location'
Fix RestContext::thePropertyEquals() to handle numeric values

Make comparison less strict since value from behat is always a string
Add test for updating a post with partial data.

Make sure missing values are ignored not removed
Add tests for posts with limit/offset and orderby/order