The version handling in LangUtil has been overhauled
to cope better with post 1.8 releases (JDK9 and JDK10 or 18.3
or whatever they call it). As part of this moved
to treating JDK9 as '9' rather than '1.9'. Also removed
duplicate version processing logic and had that defer to
the one place in LangUtil where we now deal with it.

Includes some generics tidyup in ajdoc. More ajdoc work
is necessary for Java10 because it removes the standard doclet
(old style). However trying to invoke the internal Javadoc
handler in Java10 is failing due to module visibility rules.

Modified test expectation system so it is possible to say
the test cares about one particular message and the rest
do not matter (prefix message string with '*') - crude but
quick.

Polished many places to exploit generics

Upgraded all the tests to work on Java8 - some serious changes
regarding ajdoc on Java8. Hopefully it has stayed backwards
compatible with earlier JDK versions (e.g. if using AspectJ 1.8.3+
with a JDK less than 8) but no explicit testing done for this.

Also fixed ajdoc tests to run correctly when executed via RunTheseBeforeYouCommit tests (previously they were not being run and silently failing).

- Made output class files go to documentation directory (-d) rather than source directory.

- Added "-XajdocDebug" option that will keep the source files generated from the ASM around in order to help people send better bug reports.

- Any declare forms that ajdoc doesn't know how to generate docs for get printed to the console and indicated as a limitation.

I also extended test coverage to declare forms and added proper clearing of state for multiple invocations from test cases.

for generating spacewar documentation.