Formatting fixup
Ignore generated files from testsuite.
Make the test suite run again.

When I rearranged the directory structure of Noah, I didn't run the test
suite because it was in such disarray. I have hacked the Makefile to at
least make it run again, but this needs a review. It's bloody awful.
Update testsuite.

The were some changes in how numbers are by default printed. Update the
testsuite to reflect those changes. Also formatting fixes.
Remove some debugging output.
Refactor number implementation.

I made a mistake in that all arithmetic operations stored their result
in the first argument, so in 1+2, the object holding the '1' would be
updated to now hold '3' (!) This worked fine for literal computations,
but I noticed the flaw when I tested variables, where an expression like
x:=1; x-1; x would actually indicate that x:=0. Hah.
Finish off the evaluator.

After I moved to tagged pointers, there were a few visitor I did not
update. The compiler now passes its testsuite, and the move to tagged
pointers is finally over.