Made MessageRegistry work as a non-static class.  Some refactoring is doubtlessly needed.  Still having random test failures from testRandomMovement, considering new Movement algorithm for better accuracy for version 0.6.0-alpha.
Prototyping disabling of executable messages.  Think I've got the groundwork in properly, now to add the xml junk.
Drastically improved error handling from MessageRegistry, removed a lot of unnecessary try blocks, removed unnecessary throws clauses.
Added XML parser for disabled messages, and a test disabled message.  Working on way to test disabled message.
Better SQLHandler thread safety.
Merge pull request #157 from floralvikings/executable-message-disable

Executable message disable