Improvements so we can continue to build with Scala 2.11

[jsuereth]

Here are the temporary workarounds and features to continue to build with scala 2.11. You need the following in your build to use the not-yet-merged modularization patch:

{
        name:  "scala-xml",
        system: "ivy",
        uri:    "ivy:org.scala-lang.modules#scala-xml_2.11.0-M4;1.0-RC3"
        set-version: "1.0-RC3",
        extra: {
          excludes: [{
            organization: "org.scala-lang",
            name: "scala-library"
          }]
        }
      }, {
        name:  "scala-parser-combinators",
        system: "ivy",
        uri:    "ivy:org.scala-lang.modules#scala-parser-combinators_2.11.0-M4;1.0-RC1"
        set-version: "1.0-RC1",
        extra: {
          excludes: [{
            organization: "org.scala-lang",
            name: "scala-library"
          }]
        }
      }, {
        name:  "scala",
        system: "scala", 
        uri:    "git://github.com/jsuereth/scala.git#wip/modularize-xml-parsres", //adriaanm:modularize-xml-parsers
        set-version: ${globals.scala-version}
      }

Yes, I mispelled parsers in my branch, cuz I stink. In any case, once the modules patch is merged, this will allow dbulid to build sbt projects that use scala 2.11's modules, assuming you always directly configure the scala-xml and scala-parser-combinators modules. We can fix that issue in the near future.

I've also created a temporary release 0.6.4-josh-hack-3 which has these fixes so we can limp around before better fixes exist.

Note: Feel free to cherry-pick individual fixes from here if you don't want all of it. I tried to separate everything into well-defined chunks.

Review by @cunei

[jsuereth]

Subsumed by Toni's 0.6.5 work.