I tried to make the AbstractMetric class generic for a variety of metric return types.
If someone could go over these and correct any compilation errors, that would be awesome since Eclipse was giving me a bunch of type compatibility errors that it shouldn't have.
These were the only two type compatibility errors it gave me.
avg. word length and relative letter freq. metrics
chanced integer to double
Letter pair frequency, word frequency, and vocabulary richness
Removed type variable from class header

Since the class instantiation won't recognize the return type variable,
I removed it. Also, changed some of the metrics to convert words to
lowercase as it counts. So word and Word are considered the same.
Merge branch 'GenericsAttemptforMetricsBranch' of https://github.com/peterbee/cs4250-stylometry.git

Conflicts:
	app/models/metric/AbstractMetric.java
	app/models/metric/CountWords.java
	app/models/metric/WordsPerSentence.java