Scala 2.11 compatible dependencies

 - Bump minor versions of Scalaz and Scalacheck
 - Exclude unwanted transitive depenencies of scala-compiler.
   This is a temporary measure that will not be needed after 2.11.0-M8
   as the compiler will no longer depend on the prior version of
   xml and parser-combinators.
 - Use (fully) cross built version of Shapeless

.
Explicit type annotation to help the compiler.

Workaround for:

    [error] /Users/jason/code/specs2/matcher-extra/src/main/scala/org/specs2/matcher/MatcherMacros.scala:55: No implicit view available from (_158.u.DefDef, _193.u.DefDef, _230.u.DefDef) forSome { val _158: scala.reflect.api.QuasiquoteCompatV2{val u: c.universe.type}; val _193: scala.reflect.api.QuasiquoteCompatV2{val u: c.universe.type}; val _230: scala.reflect.api.QuasiquoteCompatV2{val u: c.universe.type} } => (A1, A2, A3).
    [error]     }.unzip3