Compute context allows someone to setup the default driver, device, and stream to
use in function calls.

Base set of protocols required to move information from the host to the device as well as
enable some form of computation on a given device.  There is a cpu implementation provided for
reference.

Base datatypes are defined:
 * Driver: Enables enumeration of devices and creation of host buffers.
 * Device: Creates streams and device buffers.
 * Stream: Stream of execution occuring on the device.
 * Event: A synchronization primitive emitted in a stream to notify other
          streams that might be blocking.

Place to store global information about the drivers available to the compute
subystem.

Functions for dealing with tensors with the compute system