Updated score module to handle duplicate left-hand duplicate terms

[clpetersonucf]

Resolves #53

• Moves string comparison prep into an instance function
• For every log item, the question text (left side of pair) is compared against all other questions for duplicates. Answer text matches associated with duplicates are also considered valid, and are added to an array of possible answers. The log's answer text is now compared against all possible answers for a given log, which should now accommodate duplicate answer text (via $givenAnswer) and duplicate question text (via matches with $possibleAnswers).

Last second, unrelated fix:

• Adds validation to question bank value on save to ensure it's not set higher than the current word pair count.

[dmols]

Looks good and works as intended!