Fix quotient/examples/{lambda,sigma} given tight equality

Tidy up quotient/examples/lambda/alphaScript a little

- use Unicode quotes
- delete unnecessary infix declarations

Fix proof broken by e42271db

Clean quotient examples: now use core Mutual lib, rather than own copy

This is a start, of sorts, on having a go at github issue #10

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 revised versions of the quotient examples. The change from
(. => . | .) to (if . then . else .) caused the old versions to break.

Modified Files:
lambda/alphaScript.sml lambda/termScript.sml
lambda/variableScript.sml sigma/alphaScript.sml
sigma/objectScript.sml sigma/variableScript.sml
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Committing in a new example for the higher order quotient library.
This represents the abstract syntax of the lambda calculus, with
alpha-equivalent terms identified.

Modified Files:
README
Added Files:
lambda/MutualIndThen.sig lambda/MutualIndThen.sml
lambda/alphaScript.sml lambda/barendregt.sig
lambda/barendregt.sml lambda/betaScript.sml
lambda/etaScript.sml lambda/ind_rel.sig lambda/ind_rel.sml
lambda/liftScript.sml lambda/more_listScript.sml
lambda/more_setScript.sml lambda/reductionScript.sml
lambda/tactics.sig lambda/tactics.sml lambda/termScript.sml
lambda/variableScript.sml
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