Added comments at the beginning of all python files (except the
mmCIF code which is not originally from EMBL) with copyright and
licence information.

Added a NOTICE.txt as recommended by the Apache License docs
https://www.apache.org/dev/apply-license.html

Fixes #1

Add setup.py and reorganise for installation with pip/setuptools

Also made a few spelling and formatting changes

It turns out the script files have to be included in the
list of python packages to install in setup.py

It turns out that I misunderstood how installing
scripts with setuptools works, so I will have to
move all the scripts somewhere else again...

`pip install` succeeds, but the installed scripts do not work
because they need to be modified to account for the restructuring

sasciftools directory for all importable modules

scripts directory for executable scripts

Change license to Apache 2.0