First version of show/hide label.
It does not save label visibility right now, and I don't want it to yet.
It also has screwed up button bitmaps
Made bitmaps to go with the tools
Modifying so that instead of 'visible', the bitmap value is for 'invisible'.  This means that the default value will have the appropriate visability, and remove the need to force the label visability in the constructor.
Adding visability values to selftest.
Merge pull request #89 from calband/HideLabels

Show/Hide labels