Support 'ANY' Route Method

## ANY Routes

This adds a 'short circuit' for routes with the ANY method, so that they will match all HTTP methods (even made up ones).

The main functionality comes from the change in the router class. Instead of this:
```php
if (!$route->supportsHttpMethod($httpMethod)) {
```

I changed it to:
```php
if (!$route->supportsHttpMethod($httpMethod) && !$route->supportsHttpMethod("ANY")) {
```

Other additions include a helper method inside the Slim class (named <code>any</code>) and a unit-test in the SlimTest.php file