[FUN][IMPR][MAJ] "view" constructor

also fixes #32

src/data/Tensor.cpp

@@ -237,7 +237,7 @@ Tensor::Tensor(
         && "Requested active area is not available inside source Tensor");
     computeSize();
     // now sharing data
-    // mimpl = otherTensor.getImpl();
+    mImpl = otherTensor.mImpl;
 }
 
 void Tensor::resize(const std::vector<DimSize_t> &dims)