- [#include] Remove duplicated includes, add includes
- [attributes] add default values for mDataType, mImpl and mGrad
- [constructors] Order constructors, change array copy assignment to remove code duplication
- calling grad() does not instanciate the gradient anymore, a dedicated function should do it
- move getAvailableBackends() and operator=(const Tensor&) to cpp file
- Tensor::resize() now handles scalar Tensors

- [Add] ``zeros()`` member function to set implpementation elements to 0
- [unit_tests][NF] Add many more cases in Test_TensorImpl.cpp
- [include] update includes in Tensor.hpp

- [Add] ``zeros()`` member function to set implpementation elements to 0
- [unit_tests][NF] Add many more cases in Test_TensorImpl.cpp
- [include] update includes in Tensor.hpp

- [Add] ``zeros()`` member function to set implpementation elements to 0
- [unit_tests][NF] Add many more cases in Test_TensorImpl.cpp
- [include] update includes in Tensor.hpp

Update TensorImpl constructor to take the tensor  dimensions instead of the number of elements. Necessary for backend_opencv.

- [Syntax] Stimulis -> Stimuli and Stimuli -> Stimulus
- [#define] Use standard Aidge syntax format
- [Licence] add where missing
- [#include] add what is used and remove what is not
- [class] uniformize class member definition order
- [types] change size_t for std::size_t from <stddef> for uniformazation
- [types] change integer types for exact-width integers from <cstddint>
- Remove end-of-line spaces