message: ENH: use host/device decorator for AXOM_LAMBDA
  Default AXOM_LAMBDA to be host/device when compiled with CUDA, since,
  that is the safest. Also, added AXOM_DEVICE_LAMBDA and correspondingly
  AXOM_HOST_LAMBDA for explicit definitions.
diff: * \def AXOM_LAMBDA
  *
  * \brief Convenience macro used for lambda capture by value.
  - * \note When CUDA is used, the macro always expands to a device lambda.
  + * \note When CUDA is used, the macro always expands to a host/device lambda.
  */
  #ifdef AXOM_USE_CUDA
  -#define AXOM_LAMBDA [=] AXOM_DEVICE
  +#define AXOM_LAMBDA [=] AXOM_HOST_DEVICE
  +#define AXOM_DEVICE_LAMBDA [=] AXOM_DEVICE
  +#define AXOM_HOST_LAMBDA [=] AXOM_HOST
  #else
  #define AXOM_LAMBDA [=]
  +#define AXOM_DEVICE_LAMBDA [=]
  +#define AXOM_HOST_LAMBDA [=]
  #endif
  /*!
  