title: Get all the file Contents of a repo at Specific Commit using PyGitHub
body: <p>I want to get the file contents of all the files in the repo [changed and unchanged] using the Python [PyGitHub API]. But not sure how to achieve it. Simply, to browse the repo at that specific commit id in history. </p>
  
  <p>Is there any other API to get the required data? or can  be done with PyGitHub itself. </p>
  
  <p>Note: I'm using Github API v3. </p>