Added a few new features to AutoSongSegmentLabel
1) A button to save all data to a .mat file - this can later be used by
a different program for analysis across different days or different
batch files
2) A button to save the onsets, offsets and labels for each file as a
.txt file and as a .xls file. The .xls option does not work on linux -
will have to get it tested on windows.