Make OpenTheory Logging more robust to uptodate

If a polymorphic constant is not uptodate because of its type, the
constant itself may still be uptodate, in which case its name will not
have "old" markers to strip off.

Adjust organisation of opentheory files

This is so that files in the build sequence actually get "compiled" in a
context where they might conceivably be loaded. This is a necessary
prerequisite to getting this code compiled under Moscow ML. Sadly,
that's not possible quite yet, but does seem a worthwhile objective
eventually.