Merge pull request #39 from charman/master

Updated conversion guide with details about TextSpan/AudioSpan
Possible fix #38
Add some functionality to SuperCommunication
Update various dependencies to fix a downstream error.
Scala validation lib updates.
Fix markdown in scala/README.md
Fix links in scala/README.md
Update validatable API.
Merge pull request #40 from maxthomas/master

Fix #38
Need to rethink Java <-> scala API
Merge branch 'master' of github.com:hltcoe/concrete
Make all 'default-requiredness' fields required.