Add rhino support.

Added runner script for rhino. Also added functionality to use rhino out of box without need of manual downloading rhino. Rhino is available in maven so I added dependency to it in `project.clj`. In middleware we can get full path to rhino jar using java class methods. Unfortunately it leads to additional complexity inside middleware as now we need replace `:rhino` with several strings: `["java" "-jar" "path/to/rhino.jar" "-opt" "-1"]` but I think it worth it. 

Feel free to leave comments, happy to fix them before merge.

Nikita