Bug#506355: provide antlr library as a separate package

[Adam Heath]

package: antlr
version: 2.7.7-6
severity: minor

This package has an java antlr library, some python antlr thing, and a
system binary.  When other packages just want to make use of the antlr
jar by itself, all the other things get pulled in.

Please split this package, and provide a libantlr-java, following the
java policy in debian.