Clean up the Tensor header and get rid of the EIGEN_SLEEP macro.

unsupported/Eigen/CXX11/Tensor

@@ -33,10 +33,13 @@
   * Much of the documentation can be found \ref eigen_tensors "here".
   */
 
+#include <atomic>
+#include <chrono>
 #include <cmath>
 #include <cstddef>
 #include <cstring>
 #include <random>
+#include <thread>
 
 #ifdef _WIN32
 typedef __int16 int16_t;
@@ -48,7 +51,6 @@ typedef unsigned __int64 uint64_t;
 #include <windows.h>
 #else
 #include <stdint.h>
-#include <unistd.h>
 #endif
 
 #ifdef _WIN32
@@ -70,8 +72,6 @@ typedef unsigned __int64 uint64_t;
   #else
     #include <cuda_runtime.h>
   #endif
-  #include <atomic>
-  #include <unistd.h>
 #endif
 
 #include "src/Tensor/TensorMacros.h"