Set processed back to false after processing.

This temporary fix addresses the problem described in #810, and possibly
#945, where calls to setData for a pie chart do nothing.

jquery.flot.pie.js

@@ -270,6 +270,29 @@ More detail and specific examples can be found in the included HTML file.
 
 			ctx = newCtx;
 
+			// WARNING: HACK! REWRITE THIS CODE AS SOON AS POSSIBLE!
+
+			// When combining smaller slices into an 'other' slice, we need to
+			// add a new series.  Since Flot gives plugins no way to modify the
+			// list of series, the pie plugin uses a hack where the first call
+			// to processDatapoints results in a call to setData with the new
+			// list of series, then subsequent processDatapoints do nothing.
+
+			// The plugin-global 'processed' flag is used to control this hack;
+			// it starts out false, and is set to true after the first call to
+			// processDatapoints.
+
+			// Unfortunately this turns future setData calls into no-ops; they
+			// call processDatapoints, the flag is true, and nothing happens.
+
+			// To fix this we'll set the flag back to false here in draw, when
+			// all series have been processed, so the next sequence of calls to
+			// processDatapoints once again starts out with a slice-combine.
+			// This is really a hack; in 0.9 we need to give plugins a proper
+			// way to modify series before any processing begins.
+
+			processed = false;
+
 			// calculate maximum radius and center point
 
 			maxRadius =  Math.min(canvasWidth, canvasHeight / options.series.pie.tilt) / 2;