Throw error when rule type is not supported

fixes #82

Author: fb55

lib/compile.js

@@ -118,6 +118,13 @@ function isTraversal(t){
 function compileRules(rules, options, context){
 	return rules.reduce(function(func, rule){
 		if(func === falseFunc) return func;
+
+		if(!(rule.type in Rules)){
+			throw new Error(
+				"Rule type " + rule.type + " is not supported by css-select"
+			);
+		}
+
 		return Rules[rule.type](func, rule, options, context);
 	}, (options && options.rootFunc) || trueFunc);
 }