Update property documentation #351
Description
New-style properties (declared in class body) can have documentation attached to them whereas old-style properties (declared in __init__) did not. This allows for automation of documentation generation for those fields by defining docstrings and setting the __doc__ attribute as appropriate. A few classes have already been updated. In addition there are attributes of the property (like its value_type and inverse_of) which are now accessible for documentation generation after module load: these should be added to the doc string.
Example of a new-style properties:
class Clock(DataObject):
hour = DatatypeProperty() # <--- new-style property
''' The hour of the clock ''' # <-- documentation for the property
minute = DatatypeProperty()
''' The minute of the :py:attr:`hour` of the clock '''
maker = ObjectProperty(value_type=ClockManufacturer) # undocumentedIt may not be clear what documentation is appropriate to each attribute, but the first task is just to identify which attributes are lacking documentation.