Add nvml for GPU monitoring (squashed)

  Based on mwhite73 <marvin.white@gmail.com> implementation

  Linked to the api system

  Also fix Makefile to support standard c++ files
  This prevent nvcc use without device code

Signed-off-by: Tanguy Pruvot <tanguy.pruvot@gmail.com>

commit 38475530756de4e4dcf64c3351bdb21c875b061c
Author: Tanguy Pruvot <tanguy.pruvot@gmail.com>
Date:   Thu Nov 13 08:33:24 2014 +0100

    tmp