Removed trailing whitespace from all .sml and .sig files.

This affects over 900 files and was done using emacs's delete-trailing-whitespace
function in batch mode. Building the system with Poly/ML and Moscow ML seems to
work, so I'm hoping these changes don't break anything. Please complain if
they do!

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Committing in an alternative development for the foundations of
higher order quotients that attempts to avoid use of the
Axiom of Choice.

Added Files:
choice/README choice/dep_rewrite.sig choice/dep_rewrite.sml
choice/quotientScript.sml
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