Sycl improvements (#44)

- Eigen version bump
 - Extends Cast and Cwise ops benchmark to cover Sycl device
 - Extends device_lib_test.py to cover Sycl device
 - Registers int32, string and ResourceHandler to run on host for
   Enter and RefEnter Sycl Ops
 - Enables RecudeMax op for Sycl since Eigen implementation is ready
 - Registers Less op for Sycl device

Author: Luke Iwanski

tensorflow/core/kernels/reduction_ops_max.cc

@@ -66,7 +66,7 @@ REGISTER_KERNEL_BUILDER(
           .TypeConstraint<int32>("Tidx")    \
           .HostMemory("reduction_indices"), \
       ReductionOp<SYCLDevice, type, Eigen::internal::MaxReducer<type>>);
-// REGISTER_SYCL_KERNELS(float);
+REGISTER_SYCL_KERNELS(float);
 #undef REGISTER_SYCL_KERNELS
 
 REGISTER_KERNEL_BUILDER(