Call eval in the context of window for libraries like protoype.js

  This change calls eval in the context of the window  to be able to
  load libraries that put things in the global scope using
      var x=...
  (like prototype.js)

  Discussed at https://github.com/echo3/echo3/pull/21
Require unit test and JSLint execution prior to running 'dist' target.
Fix JSLint error.
Merge branch 'feature/gh-issue21-globaleval'
Change version to snapshot version 3.1-SNAPSHOT.