Coveralls + Specs2 2.3.13 + check command
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Tests on many implementations with separated community implementations P20-P28

Closes #22
ParallelCollections exercises

Closes #23
Scala 2.11.2 and other updates
Prevent downloading Scala 2.10.2 - see http://www.typesafe.com/blog/what-happened-to-my-travis-ci