avoid backtracking (#100)

Author: mbostock

src/color.js

@@ -6,8 +6,8 @@ export var darker = 0.7;
 export var brighter = 1 / darker;
 
 var reI = "\\s*([+-]?\\d+)\\s*",
-    reN = "\\s*([+-]?\\d*\\.?\\d+(?:[eE][+-]?\\d+)?)\\s*",
-    reP = "\\s*([+-]?\\d*\\.?\\d+(?:[eE][+-]?\\d+)?)%\\s*",
+    reN = "\\s*([+-]?(?:\\d*\\.)?\\d+(?:[eE][+-]?\\d+)?)\\s*",
+    reP = "\\s*([+-]?(?:\\d*\\.)?\\d+(?:[eE][+-]?\\d+)?)%\\s*",
     reHex = /^#([0-9a-f]{3,8})$/,
     reRgbInteger = new RegExp("^rgb\\(" + [reI, reI, reI] + "\\)$"),
     reRgbPercent = new RegExp("^rgb\\(" + [reP, reP, reP] + "\\)$"),