Feature: Player ID pages
This adds in individual pages of the type `nfl/players/:espn_id`
Also from the master list, a link to link to the individual players page. Currently this is a base implementation, as the individual players page template is simply a rerendering of the list player template. Will add a more fleshed out player id page in the future.
Merge pull request #6 from ericchen0121/player_id_pages

Feature: Player ID pages