fix(@angular/cli): Refactor skip git flag into schematics

related to angular/devkit#167

Author: Brocco

packages/@angular/cli/commands/new.ts

@@ -49,13 +49,6 @@ const NewCommand = Command.extend({
       aliases: ['si'],
       description: 'Skip installing packages.'
     },
-    {
-      name: 'skip-git',
-      type: Boolean,
-      default: false,
-      aliases: ['sg'],
-      description: 'Skip initializing a git repository.'
-    },
     {
       name: 'skip-commit',
       type: Boolean,