#7: Added TEMP_DIR to settings.py.
#2: Added `book_id` attribute to ExportRequest.
#1: Added partial implementation of LTP package creator.

Added:
 - _get_package_name()
 - _get_suffix()
 - _get_original_fn()
 - _get_metadata_fn()
 - _create_package_hierarchy()
 - _compose_info()
 - create_ltp_package()