Refactoring Tensor

Adding context to Tensor
Adding "active area" to Tensor
Forward declaring TensorImpl in Tensor instead of the another way around
CPU storage is unsigned char instead of void *
todo: memory location for device different than CPU
todo: a Tensor can share a TensorImpl with another Tensor
TensorImpl = storage
Tensor = view on storage

Notes:

• Tensor::getImpl() returns a reference not a pointer, thus client code must replace getImpl()-> by getImpl().
• Tensor.hpp does not includes backend\TensorImpl.hpp but backend\TensorImpl.hpp includes Tensor.hpp. Thus client code needs to include backend\TensorImpl.hpp (with or without Tensor.hpp)

include/aidge/operator/GenericOperator.hpp

@@ -62,7 +62,12 @@ class GenericOperator_Op
      * @return template<class T> The parameter.
      */
     template <class T>
-    T getParameter(std::string const &key) const {
+    const T& getParameter(std::string const &key) const {
+        return mParams.Get<const T>(key);
+    }
+
+    template <class T>
+    T& getParameter(std::string const &key) {
         return mParams.Get<T>(key);
     }
 
@@ -75,8 +80,8 @@ class GenericOperator_Op
     /// internal buffer in a new location (previous value is still in memory at
     /// its previous location)
     template <class T>
-    void addParameter(std::string const &key, T const &value) {
-        mParams.Add<T>(key, value);
+    void addParameter(std::string const &key, T&& value) {
+        mParams.Add<T>(key, std::forward<T>(value));
     }