Import order error

[pvnbhargava]

layout_manager.py currently has the responsibility of trying to import the optional Calibre dataprep functionality. However, layout_manager.py is imported before sys.path is configured based on information from bag_config.yaml. This means that if your BPG setup relies on setting sys.path to find the calibre dataprep class, dataprep will fail.

This can be fixed by adjusting import order in __init__.py