New class ConnectionProperties, removes hard-coded connection info
New class ConnectionProperties, removes hard-coded connection info

AGithub's "API transparency" means it could become quite usable with
many other REST APIs; but it has several hard-coded bits which refer to
the GitHub API. The new ConnectionProperties class paves the way to
genericity, by allowing us to abstract over the details of individual
REST APIs.

New class ConnectionProperties
    - which is now threaded through the Client initialization code

Client.get_connection()
    - The API base URL is now a member (api_url) of
      ConnectionProperties, rather than a hard-coded constant, in
      Client.get_connection().

mozilla/agithub,jpaugh/agithub