redo-tests: tests for redo

redo is a build tool described but not shared by Daniel J. Bernstein
<http://cr.yp.to/redo.html>.

Without a canonical release,
redo has stagnated under the weight of
competing, incompatible, and increasingly bloated 

These tests are designed using djb's description as the primary reference
and strive to specify an ideal redo that is simple, minimal, and usable.

Thanks to Nils Dagsson Moskopp for the original test suite
<http://news.dieweltistgarnichtso.net/bin/redo-sh.html>.

To run on different redos:

	git clean -df
	(export PATH=$PATH:<path to redo>; ./run)