Data Structures (syntax update)

Updated function name syntax to match the recommended python standard.
Also, syntax relating to None updated (== None to is None).
Introduction to Pattern Matching (syntax updated)

Updated syntax to match new syntax in the Trie class of the Data
Structures script.
Encoding Suffix Trees

Updated syntax to match new syntax in the SuffixTree class of the Data
Structures script.
Linguistic Complexity of a Genome (syntax update)

Updated syntax to match new syntax in the SuffixTree class of the Data
Structures script.