Add rest style 'z for mirrored-z quarter rests. (issue 200300043 by address@hidden)

[nine . fierce . ballads]

Reviewers: ,

Description:
Add rest style 'z for mirrored-z quarter rests.
The glyph was added in e3c51326b986bb56f068f70d9c5e999c5fcfc36d.

Please review this at https://codereview.appspot.com/200300043/

Affected files (+2, -3 lines):
  M lily/rest.cc


Index: lily/rest.cc
diff --git a/lily/rest.cc b/lily/rest.cc
index  
9e5dc046e14821fdced4de7ee10707c02f08b956..4f05764296c4faf61df85f892c9327293ca4d2fb  
100644
--- a/lily/rest.cc
+++ b/lily/rest.cc
@@ -199,11 +199,10 @@ Rest::glyph_name (Grob *me, int durlog, const string  
&style, bool try_ledgers,
         actual_style = "";
     }

-  if ((style == "classical") && (durlog != 2))
+  if (((style == "classical") || (style == "z")) && (durlog != 2))
     {
       /*
-        classical style: revert back to default style for any rest other
-        than quarter rest
+        these styles differ from the default in quarter rests only
       */
       actual_style = "";
     }