Use utilcpp cmake utilities.
Force minimum CMake version.
Added a CMake option to generate or not the test.
Added default constructors and removed detaching to have only value semantic usage.
Revert "Added default constructors and removed detaching to have only value semantic usage."

This reverts commit 8cf08f37a9c33a4f9c8e27c093c4f2c32c2b9887.
Simplified make_empty_sequence();
make_unique_sequence() returns by value
Removed detaching from  aosl types. (we really need some unit tests...)
Added dependencies submodule: utilcpp
Added dependencies submodule: aosl
Upgraded CMake scripts so that the dependencies are automatically used.
Tried to clarify a bit the readme file.