Add a summary report class

[tfeb]

As discussed in #34.

This is just a subclass of the plain class called summary, which suppresses the progress reports via a different default initarg. As such its summary is the same as plain's summary.

It might be better in some sense to make both plain and summary be subclasses of some common 'plain text' report class which then differ only in their default initargs, but I think that might be overengineering.

Note that I have not recreated the HTML documentation: I have added an entry for summary to documentation.lisp but I don't understand the documentation utilities well enough to know how to recreate the HTML. So that, at least needs doing.

I've bumped the minor version number: not sure if that's right.

I've tested this in my own small test suites, but not in more than one implementation and not in anything big.

[Shinmera]

Thanks! Bumping the version number isn't necessary, but it's fine. Doesn't really matter. As for recreating docs, for posterity all of my projects' docs pages can be generated via:

(ql:quickload :staple)
(staple:generate :parachute :if-exists :supersede)

Or whatever else project applies at the time. I'm not terribly concerned with regenerating the docs for every change, though.