Rewrite setup

[tomjw64]

Reorganized the package to be installed with pip. Uses setuptools with setup.py instead of a standalone setup.sh for more flexibility with regards to virtualenv and --user installs. It was then fairly easy to add the content-copy command in the process while maintaining backwards compatibility using the ./content-copy executable.
In all:

• rewrote setup,
• adds a content-copy command during setup but doesn't remove the old way
• allows setup with a virtualenv or without with --user
• updated docs to match

[karenc]

Looks good to me! 👍