[minor] Allow user to set `colors.mode`

test/core/run

@@ -29,7 +29,10 @@ var fs = require('fs'),
     path = require('path'),
     spawn = require('child_process').spawn,
     async = require('async'),
-    colors = require('colors');
+    colors = require('colors'),
+    optimist = require('optimist');
+
+optimist.argv.color && (colors.mode = optimist.argv.color);
 
 var testTimeout = 15000;
 var results = {};
@@ -57,7 +60,9 @@ function runTest(test, callback) {
   });
 };
 
-var tests = process.argv.slice(2);
+var tests = process.argv.slice(2).filter(function (test) {
+  return test.substr(0, 2) != '--';
+});
 
 if (!tests.length) {
   var pathPrefix = path.join(__dirname, 'simple');