Also provides proper associativity on the operators, to avoid
ambiguous parses.
This completes all of the examples in the Spoofax Tutorial/Reference
that use the propositional signature.
The main actions taking to restore spoofax_prop to correct operation
are not really reflected in this commit; they consisted of
switching to a Spoofax distribution of Eclipse and
updating/rebuilding
the project in various ways. However, all of the steps are now
documented here, and the narrative is extended to include the
first examples.
Resolves#1.
Also lay out the structure of the documentation and supply a decent
introduction. Also (unsuccessfully) attempt to get the first example of
a Stratego transformation from the manual implemented and documented.
