[PATCH:] chord repetition for tablature (issue 224082)

[Marc Hohl]

Hello,

Nicolas Sceaux has provided a function to store the string information
in a repeated chord for better use in tablature. I just put the definition
into the right place and enhanced ly/property-init.ly for switching
more easily to the tab repeat style.

Please have a look at

http://codereview.appspot.com/224082

Thanks,

Marc