Added the ability to generate a frequency matrix from a cipher text file and then generate a mapping between the language file and cipher file.

The usage would be:
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Import the monogrammatrix class first:
     from monogrammatrix import MonogramMatrix

Then create an instance of the class with the language file we want to build our frequency matrix from:
     monoMatrixOfLanguageFrequencies = MonogramMatrix('erictest.txt')

If the text file is only words then we have to add spaces as the most common character:
     monoMatrixOfLanguageFrequencies.setCharacterAsMostCommon(' ')

Run the method to map the mono frequencies while passing the cipher text filename as the argument:
     monoMapping = monoMatrixOfLanguageFrequencies.generateMappingBasedOnFrequencies('text_pairs/1.ciphertext.txt')

Create an instance of a guess class with the list of unique characters as the argument:
     newGuess = Guess(monoMatrixOfLanguageFrequencies.getListOfUniqueCharacters())

Assign our mono mapping as the guess
     newGuess.setGuess(monoMapping)
My test file updated to show changes/how to use new monogram function to create a mapping between language and cipher