Created a method to control where data is from and which data to use; Created a new FFT calculation class;

Control method:
-> handles where data is coming from (either from Tablet1 or from file)
-> converts data from an ArrayList<Double> type to a type double[]
array with an equivalent number of elements
-> dataToPlot (double[]) is declared as a data field, so it can be used
throughout code to simplify code in general and support readibility

Created a new class "CalcFFT.java" for FFT processing:
-> only input parameter is a double[] inputArray
-> if length of input is not already a power of 2, then it copies input
into an array that has a length of the next, nearest power of 2 greater
than the current length of the input
-> if it is already a power of 2 then it just creates a new array of
the same length and same elements
-> performs same calculations to get the FFT of data
-> instead of encoding/decoding the returned FFT array, magnitude and
power (in dB) calculations are performed in this class
-> returns the FFT array (in dB) to where function is called

Cleaned up code, removed old fft plotting methods. Try to remove
unnecessary clutter BUTTTTT.. still more work to be done to clean up
the rest of clutter