Expose interface for examining all endpoints from the spec

[striglia]

It is quite easy to generate tuples of (name, pattern, method_type) from a swagger spec and provide these for users wishing to programmatically register their endpoints with pyramid. We should provide a method you can call to return a list of objects holding this data and let callers use it as they wish.

Minimum requirements:

• Expose name (operationID in swagger 2.0)
• Expose route pattern
• Expose http method type

Possible extensions (if they're considered valuable):

• Expose request arguments (and types?)
• Summary
• Security object
• etc...