Remove breakpoint
Fix typo in comment
Remove duplicate variable

$class and $class_name were the same thing
Combine several ||= into one assignment
Fix a bug when joining two child classes that don't have tables but their parents do

The join coercion code keeps a list of joined class=>table mappings, but was
not putting in the mapping for the primary class/table the query was for.  In
the case covered by the test, it was picking the wrong class to look up a
column name for - using the source class of the join instead of the source
class of the whole query.
Fix bug with inherited implied property data_type

An object accessor's id_by creates an implied property (the thing it's id_by)
if the class definition doesn't already have that property explicitly
described.  This auto-created implied property is not given a data_type when
the property normalizer creates it.  Later on,
_complete_class_meta_object_definitions() fills in any remaining holes in the
class definition, including providing a data_type for that property.

Originally, it would always pick the data_type from the remote class' ID
property.

This fixes it to use a parent class' property of the same name (inherited)
to get the data type from first, falling back on the old behavior