musicxml2ly: multiple rights bug

[pls]

Hey all,

there can be multiple <rights> tags with or without one of the three values 
"music", "words" or "arrangement" in the identification element of a score. 
musicxml2ly v2.15.29 dumps all of them in the LilyPond variable copyright 
without mentioning the type. The content of this variable is typeset in one 
line. This makes it impossible to tell which "license" applies to which type.

multiple-rights.xml
Description: application/xml

Possible solution:
* the type value should be automatically put in front of the contents of the 
<rights> tags in the copyright variable
* if there are several <rights> tags with the same content the content should 
only be printed once, e.g. "Public Domain" or "Music & Words: Public Domain"...

hth
patrick