Ignore vendor specific tags at verb level

Vendor specific tags are now ignored at the verb level. Vendor specific tags are any tag of the form "x-something":

The intention here is to allow the vendor specific tag to apply to verbs in a path.

E.g.

...
paths:
  /posts/{id}:
    x-product: "Favorites"
    get:
      ...
    put:
      ...
...