Added empty world module
Added and tested world/resource class
Added and tested world/technology class
Added and tested world/nation-type class
Tested and corrected mechanics/battle-movement class
Tested parsing of invalid weapon XML
Finished mechanics testing
Added docstrings to the first few forms in mechanics.
Finished mechanics docstrings; also added fxtype test for fxclasses.
Added precondition and postcondition assertions to some mechanics functions
More mechanics assertions; also started adding metadata type hints for fxclass constructors
More mechanics assertions and metadata
Added mechanics assertions and metadata for the next block
Added more mechanics assertions and metadata
Added more mechanics assertions and metadata
Tested and fixed parsing of well-formed armor XML
Added more mechanics assertions and metadata
Added missing armor.xml from two commits ago
Added world/nationality fxclass
Finished mechanics assertions and metadata