add piwik installation

www/analytics/libs/sparkline/DESIGN

@@ -0,0 +1,28 @@
+#
+# Sparkline PHP Graphing Library
+# Copyright 2004 James Byers <jbyers@gmail.com>
+# http://sparkline.org
+#
+# Dual-licensed under the BSD (LICENSE-BSD.txt) and GPL (LICENSE-GPL.txt)
+# licenses.
+#
+# $Id: DESIGN,v 1.4 2008/03/11 19:12:49 jbyers Exp $
+#
+
+Not much to see.  It's 0.1, after all.
+
+Flow
+------------------------------------------------------------------------------
+
+Instantiate appropriate Sparkline subclass
+Load data, set parameters, all Set* calls
+Render
+  convert coordinates
+  calculate image size
+  create image handle
+  set colors
+  fill background
+  draw graph
+  draw features
+Optionally call Draw* functions
+Output / OutputFile