This makes some API changes to AutoDiffBlock.
- Add overload for the constant() constructor taking rvalue ref.
- Add overload for the variable() constructor taking rvalue ref.
- Make the function() constructor *require* rvalue refs.
- Add a swap() function.
The remaining changes in this commit are follow-ups especially
to the third change (adding std::move in many places), and
some removal of unnecessary block pattern arguments from calls to
the constant() static method.
Fall back to Eigen's BiCGSTAB solver if UMFPACK is not available. The
BiCGSTAB is built into Eigen and consequently always available when
Eigen is found.
Specifically,
- #include <config.h> where appropriate (all .cpp files)
- Adjust include statements to account for sub-directory locations
of .hpp files.
