Fix property builder class name
Extract basic property getter and setter

These more basic versions do not depend on the presence of property info in the
GIR. Ultimately, these basic versions should become the only versions, while any
adjustments derived from the GIR are incorporated in the special getters and
setters generated for each property by PropertyBuilder.
Move list conversion logic into getter definition
Move hash table conversion logic into getter definition
Use get_property_basic in all getter definitions
Rename Object#get_property and #get_property_basic
Limit use of #get_property_extended to the bare minimum