Merge pull request #2 from avandeursen/travis-iss1

Travis iss1
closes 1
Improve comment.
Adhere to switch statement coding style from Oracle
Fixed javadoc
Resolved various checkstyle issues.
Updated dependencies.
Merge pull request #4 from avandeursen/sonar

Coding standard compliance
Refactored with helper method to move the ghost.
fixed typo in comment.
No need for PacmanInteraction to extend Observable.
Typo in message to user fixed.
Ensured state machine consistency upon game modification.

Added explicit invariant to PacmanInteraction, which ensures
consistency between the underlying game the state machine.
Game informs via update if it has changed, and the updates 
restores consistency if necessary.
Removed obsolete unused method.
Merge pull request #5 from avandeursen/statemachine

Fixed state machine consistency.
Start upon won/lost does not invalidate invariant anymore.
Merge pull request #7 from avandeursen/restart

Start upon won/lost does not invalidate invariant anymore.
Bumping to 5.4
Merge pull request #8 from avandeursen/prepare54

Bumping to 5.4
Corrected comment lines.
Added non-negative invariant.