--added the option to filter routes by config value

This is my propose to add an ability to filter routes by specific key. For now by default all routes are added and then some of them are excluded by ```laroute => false``` key. While in many cases it is fine there are situations like mine when I use some routes that are coming from some package and I have no chance to exclude them from routing in the current way. So I came with the idea of filter option in config which allows us to set the key to filter all routes by. So if we set it to 'jsroutes' we will only get the routes that have this key set to true, but we still can set laroute to false and exlude some of them.