Updating spoofax-libs
Proper fix for cases when Tokens given to a message have no attached input.
Merge branch 'master' into hack/with-binary-libraries

* master:
  Proper fix for cases when Tokens given to a message have no attached input.
Include updated strategoxt.jar which already includes spoofax-libs and guava.
Update build.xml to not require spoofax-libs but use if it is present (otherwise use the one strategoxt.jar)
Merge branch 'master' into hack/with-binary-libraries

* master:
  Update build.xml to not require spoofax-libs but use if it is present (otherwise use the one strategoxt.jar)