uart: add C++ Uart module and links to swig

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
docs: remove references to C++ as docstrings used by sphinx

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
mraa: update to version 0.4.5

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>