No more duplication in maven-deploy.xml.

I just couldn't stand the incredible mess in there anymore. More cleanup to come.
For now, suffice it to say you need only add one line per new module.
Spin off src/library/scala/xml to src/xml/scala/xml.

Summary:
  - Remove the last vestiges of xml from Predef and Contexts.
  - Change build to compile scala.xml to scala-xml.jar.
  - Deploy scala-xml module to maven.
  - Update partest accordingly.

Note:
An older compiler cannot use the new standard library to
compile projects that use XML. Thus, skipping locker will
break the build until we use 2.11.0-M4 for STARR.

In the future build process, where we drop locker,
we would have to release a milestone that supports the old
and the new approach to xml. As soon as we'd be using that
new milestone for starr, we could drop support for the old approach.
Spin off parser combinators to scala-parser-combinators.jar.
Unfork jline: use vanilla jline 2.11 as a dependency.

Notes:
  - no longer specifying terminal by class name in scripts (using 'unix')
  - jline doesn't need a separate jansi dependency;
    it includes its own version according to:
    http://mvnrepository.com/artifact/jline/jline/2.11
Add meta-information for dbuild.

The next version of [dbuild](http://typesafehub.github.io/distributed-build/0.5.3/index.html)
will parse `dbuild-meta.json` to determine which jars are produced by a Scala build.

This way we can modularize without changing dbuild itself.

Yes, I know `dbuild-meta.json` should be generated during the build.
However, given the state of our build.xml, I think this is pointless.

My goal is to generate build.xml, dbuild-meta.json and Eclipse projects
from a higher-level description of our build. Baby steps...

Including improvements by @cunei:
  - Removing outdated field "uri" from ExtractedBuildMeta
  - Changed "partest" to "scala-partest" (the actual jar name)
Updated eclipse project files.

Set everything up so that soon-to-be independent modules are
compiled with the Eclipse plugin's compiler & library (2.11.0-M3 currently).

Most projects still compile with 2.11.0-M3, but
partest will need a nightly build of 2.11.
scaladoc needs xml and parser-combinators

Concretely, update scala-compiler's pom
to list scala-xml and scala-parser-combinators
on behalf of scaladoc.

NOTE: when spinning off scaladoc, move dependencies to its own pom
Merge pull request #2704 from adriaanm/modularize

Separate jars for XML, Parser Combinators. Use released JLine.