* Provide `morepy` extension for IPython, which:
* Installs a magic `%dev` function that opens the source locations of given
objects in an editor of the user's choice with customizable argument
format for the editor command
* Is loadable via either calling `%load_ext morepy` in the IPython shell or
calling `morepy.load(shell)` from another extension's
`load_ipython_extension(shell)` entry function