Merge pull request #171 from floralvikings/master

Merge hotfix-0.5.1-alpha into develop.
Added message arguments in preparation for new movement system.  See #162
Added lastStepTime property.
Removed constant pings.  Gumming up the test logs unnecessarily.
Set actors to move based on speed rather than at fixed intervals, still need to update to fix NPCTest
Fixed NPC class to work without frontloading move states.  Aggressive NPCs are still missing unit tests.  Closes #173
Removed all instances of Actor.STEP_LENGTH not tied to correcting positions.
Renamed MessageGenerator classes to MessageFactory classes.  Added ClientMessageFactory, ServerMessageFactory, and AgnosticMessageFactory classes and move construction of appropriate messages into these classes.
Made MessageFactory classes non-static, reduced reference leakage in constructors.
Made "id-style" Message constructor protected.
Added "position" and "time" fields to MoveState class, and modified constructors, instantiation where appropriate.
Added TODO comments for changes that should be made, relating to issues #174, #177, and #163.

Closes #176.
Added todo about hash map.
Added more timing methods and fields
Partially through reworking movement.  Tests currently broken, fixing piecemeal.
Large number of tweaks and fixes to movement.  Down to 5 failing tests.
Working on improving tests; currently generating lots of errors due to timing issues generating dozens of worlds, which is also causing heap overflows.
Reduced size of testing world.
Reduced complexity of line of sight calculation
More complexity reduction
Improving line of sight algorithm.  May be moving to player location change.