Project variables UI

![Screen_Shot_2016-04-27_at_09.01.23](/uploads/cb9b1ac42aa734cfd3271c03dfaccc12/Screen_Shot_2016-04-27_at_09.01.23.png)

![Screen_Shot_2016-04-27_at_09.01.29](/uploads/4f317014d60f205a0e29497ad20f8a2e/Screen_Shot_2016-04-27_at_09.01.29.png)

Closes #14091

See merge request !3942