@Override
            public Object exec(AceEditor editor) {
                return invokeJavaScriptCommand(jsFunction, editor);
            }
Create Ace command from javascript object.

@param obj javascript object describing Ace command
@return Ace command description object
stroom-core-client-widget/src/main/java/edu/ycp/cs/dh/acegwt/client/ace/AceCommandDescription.java