Adding vagrant dependency to intial setup instructions.
Updating tar.gz download URL to include version-specific subdirectory.
Merge pull request #175 from fnaard/ticket/TRAINVM-50/add_subdirectory_to_pe_url

Updating tar.gz download URL to include version-specific subdirectory.
Adding screen and zsh to base install.
Merge pull request #176 from fnaard/ticket/TRAINVM-37/add_screen_zsh_packages_to_bootstrap

Adding screen and zsh to base install.
Merge pull request #172 from fnaard/add_vagrant_to_initial_setup

Adding vagrant dependency to intial setup instructions.