use much faster regexp for ansi coloring

ansispan function adapted from mmalecki/ansispan

The easiest way to see how slow the old way was is to create a very large traceback (e.g. max recursion), which bring everything to a screeching halt (even future page loads, if the output is saved).  Now a max recursion error draws in a second or two.

closes  #3198

IPython/frontend/html/notebook/static/js/utils.js

@@ -158,12 +158,34 b' IPython.utils = (function (IPython) {'
 
     //Map from terminal commands to CSS classes
     var ansi_colormap = {
-        "30":"ansiblack", "31":"ansired",
-        "32":"ansigreen", "33":"ansiyellow",
-        "34":"ansiblue", "35":"ansipurple","36":"ansicyan",
-        "37":"ansigrey", "01":"ansibold"
+        "01":"ansibold",
+        "30":"ansiblack",
+        "31":"ansired",
+        "32":"ansigreen",
+        "33":"ansiyellow",
+        "34":"ansiblue",
+        "35":"ansipurple",
+        "36":"ansicyan",
+        "37":"ansigrey"
     };
 
+    function ansispan(str) {
+        // ansispan function adapted from github.com/mmalecki/ansispan (MIT License)
+        Object.keys(ansi_colormap).forEach(function(ansi) {
+          var span = '<span class="' + ansi_colormap[ansi] + '">';
+
+          //
+          // `\033[Xm` == `\033[0;Xm` sets foreground color to `X`.
+          //
+          str = str.replace(
+              new RegExp('\033\\[([01];)?' + ansi + 'm', 'g'), span
+          );
+        });
+
+        str = str.replace(/\033\[([01]|39|22)?m/g, '</span>');
+        return str;
+      };
+    
     // Transform ANSI color escape codes into HTML <span> tags with css
     // classes listed in the above ansi_colormap object. The actual color used
     // are set in the css file.
@@ -179,19 +201,9 b' IPython.utils = (function (IPython) {'
         // all ANSI codes that do not end with "m".
         var ignored_re = /(?=(\033\[[\d;=]*[a-ln-zA-Z]{1}))\1(?!m)/g;
         txt = txt.replace(ignored_re, "");
-
-        while (re.test(txt)) {
-            var cmds = txt.match(re)[1].split(";");
-            closer = opened?"</span>":"";
-            opened = cmds.length > 1 || cmds[0] != 0;
-            var rep = [];
-            for (var i in cmds)
-                if (typeof(ansi_colormap[cmds[i]]) != "undefined")
-                    rep.push(ansi_colormap[cmds[i]]);
-            opener = rep.length > 0?"<span class=\""+rep.join(" ")+"\">":"";
-            txt = txt.replace(re, closer + opener);
-        }
-        if (opened) txt += "</span>";
+        
+        // color ansi codes
+        txt = ansispan(txt);
         return txt;
     }