Change to use path to normalize phpunit command. This should allow th…

…e command to work on all OS's (Currently on windows it doesn't work because the path uses forward slashes).

src/tasks/phpunit.js

@@ -1,5 +1,6 @@
 import runTests from './shared/Tests';
 
+var path = require('path');
 /*
  |----------------------------------------------------------------
  | PHPUnit Testing
@@ -15,6 +16,6 @@ Elixir.extend('phpUnit', function(src, command) {
     runTests(
         'PHPUnit',
         src || (Elixir.config.testing.phpUnit.path + '/**/*Test.php'),
-        command || 'vendor/bin/phpunit --verbose'
+        command || (path.normalize('vendor/bin/phpunit') + ' --verbose')
     );
 });