Check for invalid paths

[ronag]

Breaking out from #214.

Json paths should be checked for validity. Currently the behaviour for invalid paths is pretty much undefined.

[yasserf]

I would probably suggest we deprecate our path notation (which is built around our random thing) and use a third party library like jsonpath. Only issue is its almost 7000 lines, so might be just add an option in V4 to allow custom JSON path libraries.

This would need to be used in both the server and JS, but the server can easily take the extra 80kb weight as a dependency.

[yasserf]

Yeah I’m still 100% for getting rid of our custom paths and using an actual json path implementation. raising this as a V5 issue

[yasserf]

Closing in favour of deepstreamIO/deepstream.io#1046