publish version w/fixed test

Allow keeping one-sided dice, improve docs

The documentation was missing a few examples and clarifications, and
implied that subsets of one-sided dice rolls could be kept.  Although
it's weird to keep some one-sided dice, it's not impossible, so now it's
implemented.

Fudge/Fate dice also can be kept, although neither d1 nor dF can
explode.

Add documentation.

add metadata

fix minus AGAIN