Allow packages as possible extraction targets for extractor extractions
Fix unapply's result values for extractors providing no bindings

In Scala 2.11 extractors providing no bindings have to have a return type of `Boolean`. Returning an `Option[()]` is no longer possible (see https://issues.scala-lang.org/browse/SI-6111).
Fix indentations in ExtractExtractor test cases
Merge pull request #58 from Luegg/extendExtractExtractor

Extend ExtractExtractor