modified rest.py: fixed 'monkey patch' to overcome 'wrap_socket_patched() got an unexpected keyword argument 'ciphers'' error with sleekxmpp

- updated macros
- removed unneeded fields
- removed trailing whitespace
- updated license

so that /usr/bin/gracedb comes from the python2 package, not python3

This reverts commit a9a83539.
The pluggy developers rapidly released a new version (0.11.0)
which fixed the issues in 0.10.0.

Recent release of pluggy (0.10.0), which is a dependency of pytest,
does not properly declare its dependency on importlib_metadata.

'info' better describes the functionality. 'show' is kept as a
legacy command for the time being, with the same functionality
as 'info'.

These will not be shown in the main 'gracedb --help' but will
still have their own functional help and will work as expected.

Documentation will be hosted on readthedocs since the capability
of maintaining separate documentation for different versions
is available there and seems quite useful.

Remove all calls to dict.keys() and dict.values() and replace with
calls that are compatible with both Python 2 and 3.

Modify to use short and long descriptions for commands.
Also parse delimited arguments automatically.