Order operation based on position #317

To @adrianbk,
your fix on #317 to sort ApiOperationReader doen't work. This is because ApiOperationReader is called for every request mapping on @ApiOperation not for all requests on controller. The sorting is then done only if request has more supports method as POST and GET. (for (RequestMethod httpRequestMethod : supportedMethods)]
The sorting must be done on ApiListScanner. First problem which I saw there, is using set not list (then the order is not how request is red, but randomly). I change set to arrayList and the sort on apiDescription.

Milan