Implement like operator

Added missing operator.

How to test:

var _foo = require("./models/foo");
var str_search = "%test%"; //  you can use "test%" or "%test"
_foo.all({where:{name:{like:[str]}}},function(err,result1){
	console.log("like:" + result1.length);
	_foo.all({where:{name:{nlike:[str]}}},function(err,result2){
		console.log("nlike:" + result2.length);
	});
});