[dia] drop unused cellrenderer experiment

[Zander <zbrown src gnome org>]

commit e77f343e92f0095581d01a431e898b0d34b60ad5
Author: Zander Brown <zbrown gnome org>
Date:   Sun Nov 24 23:08:42 2019 +0000

    drop unused cellrenderer experiment
    
    doesn't actually do anything

 lib/diacellrendererproperty.c | 363 ------------------------------------------
 lib/diacellrendererproperty.h |  69 --------
 lib/meson.build               |   1 -
 3 files changed, 433 deletions(-)
---
diff --git a/lib/meson.build b/lib/meson.build
index c8d53c87..776b21e7 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -152,7 +152,6 @@ libdia_sources = stdprop_sources + [
     'dialib.c',
     'diacontext.c',
     'diacellrendererenum.c',
-    'diacellrendererproperty.c',
 ]
 
 gnome = import('gnome')