Fixed a bug were buffer geometry files were missing the `data` key
PEP8 cleanup

More PEP8 conforming for the api package

Added a test scene for scenes with children

Fixed an issue were rotations were being recorded as Euler and not as Quaternion
Fixed an issue were duplicate geometries were being recorded to the scene

updated the bone mapping logic to instead record the maps locally within the parsing method and not store to the Geometry() instance
included package modules missing from import
cleanup of unused imports and variables

renamed custom Blender properties to THREE_ prefix
renamed the "round" attributes to "precision"
fixed a bug in review where it was trying load morph targets when there wasn't any

merged exporter.constants with package constants
replaced threeio name with three/io_three naming conventions
fixed a bug were exporter.geometry was logging errors with incorrect formatting
fixed a bug were exporter.geometry was reporting, via logger, on data results incorrectly
migrated over main addon code
still needs testing, not ready for merging