Reverse deprecation of pie chart props

documentation/md/style.md

@@ -338,6 +338,18 @@ The following is an example of valid background image styling using JSON. The ex
 ```
 
 
+## Pie chart background
+
+These properties allow you to create pie chart backgrounds on nodes ([demo](demos/pie-style)).  Note that 16 slices maximum are supported per node, so in the properties `1 <= i <= 16`.  Of course, you must specify a numerical value for each property in place of `i`.  Each nonzero sized slice is placed in order of `i`, starting from the 12 o'clock position and working clockwise.
+
+You may find it useful to reserve a number to a particular colour for all nodes in your stylesheet.  Then you can specify values for `pie-i-background-size` accordingly for each node via a [mapper](#style/mappers).  This would allow you to create consistently coloured pie charts in each node of the graph based on element data.
+
+ * **`pie-size`** : The diameter of the pie, measured as a percent of node size (e.g. `100%`) or an absolute length (e.g. `25px`).
+ * **`pie-i-background-color`** : The colour of the node's ith pie chart slice.
+ * **`pie-i-background-size`** : The size of the node's ith pie chart slice, measured in percent (e.g. `25%` or `25`).
+ * **`pie-i-background-opacity`** : The opacity of the node's ith pie chart slice.
+
+
 
 
 ## Edge line

src/style/apply.js

@@ -433,10 +433,6 @@ styfn.applyParsedProperty = function( ele, parsedProp ){
     self.checkTriggers( ele, prop.name, fromVal, toVal );
   };
 
-  if( prop && prop.name.substr(0, 3) === 'pie' ){
-    util.warn('The pie style properties are deprecated.  Create charts using background images instead.');
-  }
-
   // edge sanity checks to prevent the client from making serious mistakes
   if(
     parsedProp.name === 'curve-style'