LilyJAZZ-README: Update to clarify licensing situation

Author: uliska

custom-music-fonts/LilyJAZZ/README.md

@@ -1,4 +1,27 @@
-This folder should hold the code to use the lilyJAZZ fonts/settings.
-As the original developer Torsten Hämmerle seems to be unavailable
-we decided to offer this space to access and improve the great
-LilyPond add-on.
+## LilyJAZZ
+
+In March 2013 Torsten Hämmerle sent a wonderful LilyPond add-on to the
+lilypond-user mailing list: **LilyJAZZ**. Read his original announcement in [this
+message](http://lists.gnu.org/archive/html/lilypond-user/2013-03/msg00647.html).
+LilyJAZZ offers a JAZZ Music and a JAZZ Text font along with tools to
+integrate them in LilyPond.
+
+#### Disclaimer:
+The licensing status of this material isn't completely clear. The original developer
+isn't available and can't be contacted through email or phone anymore.
+Therefore we can only rely on his original post where he states that
+
+> the whole LilyJAZZ issue shall be open and free (just like Lilypond), so I first  
+had to create my own fonts in order to become independent of commercial ones.
+
+We consider this as a release under the same licensing model as LilyPond (i.e. GPL).
+"shall be" is surely not meant as a temporal expression but as an expression of intent
+(it is probably inexactly translated from the German "soll sein", not from "wird sein").
+Torsten surely meant that having created the fonts was the prerequisite for being
+able to release it under a free license, and not that making the material available
+in that message was the prerequisite to release it "open and free" at some undetermined
+point in future.
+
+#### Usage:
+
+To use **LilyJAZZ** you have to [please continue ...]