Make get_sig_pitch not change directories when calling Praat

[cwnaber]

Low priority.

Change these lines

        curr_dir = pwd;
        temp_str = which('get_pitch_tracks.praat');
        wave_viewer_path = fileparts(temp_str);
        cd(wave_viewer_path)

Then also change where the file gets read from in readtable

Then also change the delete function