[#524] (rm, ogl) Added MapLocation class with unit tests.
[#524] (rm, ogl) Added MapLocation.ORIGIN and related convenience methods.
[#524] (rm, ogl) Added initial MapCluster implementation.
Implementation and tests for single location clusters only.
[#524] (rm, ogl) MapCluster now counts number of locations in cluster.
Reworked isEmpty() method based on location count rather than origin detection.