Javassist 3.21.0 for Java 9 early access

Initial test release for Java 9.

Javassist 3.20.0-GA release

This release includes a few bug fixes.

Javassist 3.19.0-GA

Including a number of bug fixes and Java 8 supports.
To check the version number, do the following:

java -jar javassist.jar

Javassist 3.18.2-GA

The source files are the same as rel_3_18_2_ga but javassist.jar was rebuilt for the release.