adjust plai's test facility to print test failures to stderr
instead of stdout (in addition to making errors red in drracket,
this will also make some of the existing test suites more
drdr friendly)
Rackety

This commit is to giure out just how much Rackety can combat rightward drift
in this file (this was a region of code edited recently for other reasons)
Turns out that the first hunk's rightmost column (of code, not counting
comments) moved left by 39 chars and the second by 40 chars
fix a bug in ->i parsing