Use Unicode quotes in some self-test output

implement simple quantifier heuristics

The quantifier heuristics library is powerful, but often slow. The
unwind conversions are fast, but have serious restrictions. This commits
adds simple quantifier heuristics. They are based on the techniques
developed for quantifier heuristics library, but only search gap guesses
that don't contain free variables. Some very limited experiments suggest
that it is similarly fast as unwind. It can handle all the cases unwind
can handle. However, it supports also a much richer syntax. Moreover, it
can instantiate in addition to universal and existential quantifiers
also unique existential quantifiers, eliminate select and some.
Moreover, it knows about pairs and lists.

fix selftest of quantHeuristicsLib

The recent changes to how context is processed were unluckily
not propagated to the selftests. This fixes the resulting errors.

Delete trailing whitespace in src/

This needs doing periodically, and is best done to a whole bunch of files
at once.

trailing newlines in *.{sml,sig} files from src/ removed

Trailing newlines from SML files in src/ were rendered in HTML documentation.

Fix quantHeuristics selftest to cope with change in cd00950

quantifierHeuristics tweaks
- some tweaks to make sum_qp behave nicer
- for this some small changes that can be seen as
bug fixes or minor feature improvements

quantHeuristicsLib bug fixes

- back-chaining only applied weakening, if a rule could be applied
for both threngthening and weakening
- trouble with free type-variable clashes fixed

Delete trailing whitespace in src/

bug-fix in Sanity.sml another cleanup of quantHeuristicsLib

extended interface for quantifier heuristics

Now additional context as well as lemmata used for weakening / strengthening can be added to quantifier heuristic parameters.

Added support for context to quantifier heuristics, add sum_qp

cleanup of quantifier heuristics library

- more sensible names for guesses
- quantHeuristicsLib renamed to quantHeuristicsLibBase
- quantHeuristicsLibArgs renamed to quantHeuristicsLibParameters
- new shorter signature defined in quantHeuristicsLib
- adaptation of usage of quantHeuristicsLib

More on quantfier heuristics (I did not add all changes to the first commit)

Remove trailing whitespace in source files.

fix problem in selftest with standard-kernel

fixed a minor bug with free vars in quantHeuristicsLib, selftest now terminates when encountering a problem

- reimplementation of quantHeuristicsLib.
- move parts of quantHeuristicsLib to quantHeuristicsTools
- selftest added

Before guesses were justified by hand crafted theorems. There were modified using low level forward proof techniques. This resulted in quantHeuristicsLib being hard to understand and maintain.

This reimplementation exploits recent addition to pairTools about handling paired quantification in order to introduce general predicates for guess theorems. Defining special predicates allows proving general lemmata easily. quantHeuristicsLib can the use the lemmata instead of low level proofs. However, this comes with the additional cost of introducing and eliminating tupled quantifiers.

The new version is easier to understand and maintain. Moreover, it became much simpler to add user specified heuristics. The behavior changed slightly. For example, unnecessary priming of newly introduced variables has been eliminated.