Add publishedApiDoclet library, and ant task which uses it

This is a library which uses a javadoc doclet will publish only those classes/methods which contain a
particular tag in their javadoc. We've been using an annotation. Still need to modify the relevant methods.

IGV-1882 #comment
Add source for publishedApiDoclet

We add it here because it seems like the library is abandoned and we don't want to lose it. License is LGPL 2.1, compatible with ours, although since we aren't including it in the build that's not completely necessary.

IGV-1882 #comment
Change from using @api annotation to @api javadoc tag

IGV-1882 #comment
Change javadoc tags

 user: -> @author
 date: -> @date
Merge branch 'master' into Javadoc2

Conflicts:
	src/org/broad/igv/feature/genome/Genome.java
	src/org/broad/igv/feature/genome/GenomeManager.java
	src/org/broad/igv/ui/IGV.java
Merge pull request #41 from broadinstitute/Javadoc2

Javadoc2

Add ant task (and necessary library) for creating javadoc ONLY for those elements with an "@api" tag in the javadoc