In the rewrite the vector types of UMPack were checked, similar to the
other direct solvers. This does not work anymore, as recent changes in
UMFPack now lead to a compiler error if the vectors are not available,
i.e. when using a real-type different from double. This change now
(re-)introduces a SFINAE check to ensure that the types are compatible.

cleanup a range of warnings

See merge request !583

Catch polymorphic type ISTLError by reference

See merge request !581

Found by GCC (Wcatch-value)

Update changelog release 2 10

See merge request !576

Update versions release 2 10

See merge request !575

Improve UMFPack vector chooser

See merge request !546

Fix misc warnings

See merge request !574

* Assign unused arguments to std::ignore to avoid warnings

Fix more Cppcheck findings

See merge request !571

Found by Cppcheck (unreadVariable).

Found by Cppcheck (unreadVariable).

Found by Cppcheck uselessOverride).

Avoid unwanted copies of the iterator.
Found by Cppcheck (postfixOperator).

Found by Cppcheck (missingInclude).

Update LICENSE.md

See merge request !573

setupLaplacian: Add optional diagonal regularization

See merge request !539

This generalizes the necessary regularization for the umfpacktest and
makes it usable for other algorithms. A hint in Cholmodtest is added and
the other tests using this methods are kept unchanged.

The method was also cleaned up and modernized.

Co-authored-by: Santiago Ospina De Los Ríos <sospinar@gmail.com>

Move include of config.h from source to some header files

See merge request !566

[bugfix] Make solverfactory tests work without optional pkgs

Closes #117

See merge request !570