Finish up value namespace, and other starting points.

- Add the following to the DSLink.Value namespace.
  - DGBooleanValue
  - DGDoubleValue
  - DGIntegerValue
  - DGLongValue
  - DGPrimitive
  - DGStatus
  - DGStringValue
  - DGValue

- Started API namespace with the following
  - DGContext
  - DGMetaData
  - DGType

- Unfinished table placeholder.