Remove "Add new" from menu and admin pages

Applies to https://github.com/GigaOM/gigaom/issues/6323

![screen shot 2014-12-08 at 8 31 00 pm](https://cloud.githubusercontent.com/assets/929375/5350876/8aa74e38-7f19-11e4-9b58-2ef0c995973b.png)
![screen shot 2014-12-08 at 8 31 08 pm](https://cloud.githubusercontent.com/assets/929375/5350879/8aab3bb0-7f19-11e4-8893-54191463952c.png)
![screen shot 2014-12-08 at 8 31 58 pm](https://cloud.githubusercontent.com/assets/929375/5350877/8aa9250a-7f19-11e4-8a4c-e9616b1ba441.png)