Todo:
* Install System
* Required dependencies (if OCULUS is on, OCULUS_SDK_PATH is required)
* C+11 building setting for Linux

so updating them to latest remote hash does not tags blender repository
as changes. But it is still possible to make changes to
submodules and commit them from their path.

(copied this from Blender)

* Kernel no longer required
* Update instructions to use submodule

Up is always Y though