Restructure file layout
Preliminary GUI
GUI stuff
Fix formatting of graphs

Remove first and last tick label to prevent overlap of axis unit label.
Reduce numer of ticks when drawing loudest graph. Round loudest tick
labels to nearest 2 decimals.
Remove AudioLab as requirement
Update version number, add pymasvis to output filename
Calculate hist using raw data
Remove junk code
Update readme
Increment version number
Fix file type check
Increment version number
Set correct range of histogram
Calculate checksum
Tweak histogram graph to show values of 1
Make span marker more visible
Skip channel if no peaks are found
Modify output filename suffix
Return output filename
Lots of GUI functionality