Added version to composer.json

This fixes #1997 by adding the `version` key to the `composer.json`
file.  The version number will be updated with newer releases as
well.
Fixed reversed gradients, again

The gradients that were fixed in #2002 had the wrong target value.
Most of them were targetting the bottom, though not all of them,
and the code set them to target the top.
Gradients are all set now