Werror: Enable warnings as errors

Added C/CXX warning messages similar to MRAA (w/ -Werror).

    * Added syslog warning for missing switch cases
    * Cleaned up uint vs int usage
    * Fixed redifinition errors for C structs
    * Added virtual destructors for base classes
    * Removed redundant CMAKE_CXX_FLAGS from COMPILE_FLAGS for all three
      wrapper languages.  The CMAKE_CXX_FLAGS were showing up twice in
      the compile commands for the wrappers.
    * Added CMake WERROR option to enable/disable warnings as errors for
      all targets.
    * Disable a handful of compiler warnings for the wrapper cxx files,
      this minimizes the number of warnings from auto-generated code).

Signed-off-by: Noel Eck <noel.eck@intel.com>

examples/c++/nrf8001-broadcast.cxx

@@ -122,6 +122,8 @@ main(int argc, char **argv)
                             lib_aci_broadcast(10/* in seconds */, 0x0100 /* advertising interval 100ms */);
                             printf ("Broadcasting started\n");
                         break;
+                        default:
+                        break;
                     }
                 }
                 break; //ACI Device Started Event
@@ -156,6 +158,8 @@ main(int argc, char **argv)
                 case ACI_EVT_HW_ERROR:
                     printf ("ACI_EVT_HW_ERROR\n");
                     break;
+                default:
+                    break;
             }
         }