Fixes #473, catches outdated player names and checks if all entries are UUIDs before converted and thus prevents the server crashing.

Split off logic into single responsibilities for storing, initializing and matching the UUID mappings. Added JUnit to create tests for the UUID Matcher to see if its legit. It tests against simple problems like unconform UUIDs and also tests against a valid UUID.
Drop crank if fake player uses it
Enhancement: put IMC handling into separate class

Clarify documentation
Merge pull request #500 from thatsIch/enhancement-imchandler

Enhancement: put IMC handling into separate class
Merge pull request #516 from TheJulianJES/CrankFakePlayer-Fix

Drop the wooden crank if a fake player trys to use it
Merge pull request #480 from thatsIch/uuid

Fixes #473, catches outdated player names and checks if all entries are UUIDs before converted and thus prevents the server crashing.