a2_self_test is used to ensure the author functions has the right names and output. Not needed to run the program.
author_functions contains functions to parse the text in the mystery text.
author_program is used to run the author_functions. The program will ask for the mystery text to test against the signature files which
determine which text closely resembles text from which author. 

Mystery text files: These text files do not have an author associated with them but uses the author_functions to calculate the similarity 
to the authors from the signature folder.