Update versions.
Downgrading to 2.11.2 because of

https://groups.google.com/forum/#!topic/scala-internals/SSD9BNJaFbU
Merge branch 'master' into equality
changed wrong equals, but it breaks monoid
add some more specific test cases that fail
use a map of sheets for Workbook to make Workbook a proper Monoid
skipping Workbook tests again
Merge pull request #39 from rintcius/workbook-equals

Fix for workbook equal
Merge remote-tracking branch 'upstream/master' into equality