Add reporter which generates Github-flavoured markup tables.

lib/reporters/gfm.js

@@ -0,0 +1,45 @@
+
+/**
+ * prints results in a Github-flavored markdown table. Only works 
+ * with batch benchmark data
+ */
+
+function Reporter(){
+	this.out = process.stdout
+}
+
+Reporter.prototype.report = function(name, results, iterations){
+    var out = this.out
+
+    out.write('\n' + name + ' x' + commaGroups(iterations))
+    out.write('|total (ms)|average (ns)| diff (%)\n')
+    out.write(':--|--:|--:|--:\n')
+
+    results.sort(function (a,b) {
+        return a.total - b.total
+	}).forEach(function(r) {
+        out.write(r.name);
+        out.write('|' + formatNumber(r.total / 1e6, 0))
+        out.write('|' + formatNumber(r.total / iterations, 0))
+        // diff to fastest
+        out.write('|' + formatNumber(difference(results[0].total, r.total), 0))
+        out.write('\n')
+	})
+}
+
+function difference(r1, r2) {
+	// can't devide by zero
+	return ((r2 - r1) / (r1 || 1)) * 100
+}
+
+function formatNumber(x, n) {
+	return x === 0 ? '-' : commaGroups(x.toFixed(n))
+}
+
+function commaGroups(value) {
+	var parts = value.toString().split('.')
+	parts[0] = parts[0].replace(/\B(?=(\d{3})+(?!\d))/g, ',')
+	return parts.join('.')
+}
+
+module.exports = Reporter