Add javadoc links to dependencies in project.xml

(originally filed by Tim McCune)

It would be nice to be able to specify the URLs that are currently in maven.javadoc.links in project.properties in my project.xml. For example:

<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>3.8</version>
  <api>http://junit.sourceforge.net/javadoc</api>
</dependency>

It would also be nice to be able to specify a JDK version in project.xml and have Maven automatically link in the javadoc API for that version of the JDK. Specifying the JDK version in project.xml would also allow Maven to make intelligent assumptions about stuff like maven.compile.source, maven.compile.target, maven.javadoc.source, maven.test.source, etc. It's really annoying to have to specify at least 4 separate properties in project.properties for every project just because I'm using JDK 1.5.