Revamp how split points are obtained

[ ADDED ]  New logic to figure out how split points should be determined
           from the CUE file.  If there are pregap (INDEX 00) entries in
           a CUE file, then these will be skipped when splitting audio.

           If the pregap is more than 2 seconds in length, we'll include
           the pregap as part of the audio (as it most likely contains
           audio - hidden track, transitional audio, etc)
Documented the changes made to split points

[ ADDED ]        Lots of documentation regarding how the starting and
                 ending split points are obtained
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[ ENHANCEMENT ]  Cleaned up various variables and made the code more
                 readable