Redefine the seal_container interface. New interface create_container.
Improve the help information.
Move the callings to index_search from filter_thread to prepare_thread to simplify the implementation of new filter.
Adjust the position of code to clearly present the six phases of dedup.
Fix two silly mistakes introduced while clearing up the code.
Move callings to index_search() back to filter phase.
Miswrite a variable's name
Small modifications.