Add .repository_network_events

Covers the endpoint to get events from a repository's network.

http://developer.github.com/v3/activity/events/#list-public-events-for-a-network-of-repositories
Add .organization_public_events

http://developer.github.com/v3/activity/events/#list-public-events-for-an-organization
Add .received_public_events(user)

http://developer.github.com/v3/activity/events/#list-public-events-that-a-user-has-received
Add .user_public_events

http://developer.github.com/v3/activity/events/#list-public-events-performed-by-a-user
Add .organization_events

http://developer.github.com/v3/activity/events/#list-events-for-an-organization