Read in a .jar file and parse and register classes for use by Axe.
(read-jar jar-path &key :dir ; default nil :classes ; default :all )
A path to a .jar file, relative to the directory indicated by the
Classes to read from the .jar. Either
:all, or a list of strings representing class or interface names (usually fully-qualified). Note that using :allon a large .jar file may cause a huge amount of code to be read in.