Adding the `trix` prototype tool and our test matrix.

trix can run test matrixes. The matrix for our very own
tests is located on test/matrix.sh. The test/README.md was
updated to reflect those changes.

Boxes with unstable provisioning were removed from the
Vagrantfile.
Moved text from README.md to split doc/*.md files.

Each tool now has its own doc entry. Documentation was structured
but largely unfinished.