GROOVY-5068: SecureASTCustomizer receiver needs documentation
Updated @Memoized so that it works with @CompileStatic
   * slightly changed the strategy (private method + closure field)
   * typed the closure field
   * fixed variable scope
remove commented out "evaluationDependsOn(':')"
Merge pull request #215 from PascalSchumacher/GROOVY-5068

GROOVY-5068: SecureASTCustomizer receiver needs documentation
Updated @Memoized so that it works with @CompileStatic
   * fix implicitThis on method call expressions