Initialisation step for Github Pages

Used to check/ set any Github Pages environment variables

Performs the required steps for publishing to Github pages

• runs npm run generatedocs
• git fetches the gh-pages branch of the project into a throwaway git repository
• copies the documentation generated by the generatedocs script into the gh-pages branch
• copies any additional files required into the gh-pages branch
• if any files have changed, git commits git pushes on the gh-pages branch
  • this is when the files actually succeed in publishing
• if necessary, cleans up the throwaway git repository