Add support for transparent facades action in gates

As suggested in #1816 I had add "transparent facades" action for gates.
Can be useful for debugging some hidden pipe systems.
Couple screenshot:
![screenshot from 2014-05-18 01 13 01](https://cloud.githubusercontent.com/assets/1416030/3005558/ae7dfee8-dde7-11e3-8fe4-b1871375fdf4.png)
![screenshot from 2014-05-18 01 13 13](https://cloud.githubusercontent.com/assets/1416030/3005556/ae6a61a8-dde7-11e3-8e78-6b2d06ac1174.png)
![screenshot from 2014-05-18 01 13 24](https://cloud.githubusercontent.com/assets/1416030/3005557/ae7430e8-dde7-11e3-918a-5c8e83f17bab.png)