FIX: add line for check duplicates_save_path is None

DEL: remove deprecated functions

NEW: update requirements add spark downloading GraphFrame code

DOCS: chores

ENHANCE: update docstring and minlengh filter

ENHANCE: change join logic and add duplicates_df save step

ENHANCE: compose connected component with GraphFrame

ENHANCE: update signature function with enhanced udf

DEL: remove signature rdd

ENHANCE: change tokenizer and ngram to spark.ml

REFACTOR: update params

ENHANCE: check whether id_col exists if not create

ENHANCE: duplicates_save_path check (is existed)

ENHANCE: separate dataframe DAG start point

DOCS: add the removed file, another option for not cloning (#11)