Get rid of 2 large max_vals arrays that are unused

[Richard Elkins]

Currently,

    Class used to initialize some maximums.
    """
    def __init__(self):
        self.maxsnr = None
        self.maxdrift = None
        self.maxsmooth = None
        self.maxid = None
        self.total_n_hits = None

Note that

• maxsmooth is unused except to initialise them to float zeros for a length of FFT length each.
• maxid is set to a value in hitsearch but not used for anything else.

Will remove them and their initialisation.

[Richard Elkins]

Also, while modifying find_doppler.py,

• Get rid of a needless return of a filewriter object by tophitsearch.
• Get rid of unused "reverse" parameter for hitsearch(). The value was always 0 (don't do that). The caller is performing the spectrum reverse where required.
• Added more comments.