Expanded Netlink functionality to configure and query the CAN interface.

• #32 Further expanded netlink functionality:
  • Added setters for most additional interface CAN parameters
  • Ability to query back interface CAN parameters
  • ExpandedInterfaceDetails to include CAN-specific parameters
  • Better integration of low-level types withneli
  • Significant cleanup of thenl module
  • Split thenl module into separate sources for higher and lower-level code