A static cast in vc deriberately says, that the third
and forth template parameter must not be set manually.
Hence this patch disables the tests where this is done.

`Simd::cond(a,b,c)` only has overloads for the cases where
`b` and `c` have the same type. If this is not the case
(which seems to happen for certain distributions and compilers)
the compiler cannot deduce the template parameter for the type.

It turns out that in all cases where this happens, the first
argument is constructed by explicitly casting to a type. In
all these cases the present patch adds a cast to this type
for the second argument, too.

WARNING: I did not look at what the actual code does. However,
if the implementation of `Simd::cond()` makes and the existing
cast make any sense, that's the only possible type we can commit to.

Fixes compilation with SuperLU 7 by forcing backwards compatibility

See merge request !591

SuperLU 7.0.0 now uses singlecomplex instead of complex and by default
does not add a typedef to make singlecomplex available as type
complex. The latter was used in previous versions.

As we need to support several versions of SuperLU we force adding such
a typedef by defining SUPERLU_TYPEDEF_COMPLEX

Replace pthread_exit(NULL) calls by return NULL

Closes #121

See merge request !589

Get rid off unused-variable-warnings.

See merge request !579

Fix constructors in iterators

See merge request !584

Update set_package_properties for ARPack and SuperLU

See merge request !585

Improve support with MSVC

See merge request !577

* Handle float exception handling for MSVC
* Remove system specific includes
* Make iterator in block vector be copyable to fulfill output iterator interface

simplify and cleanup the SolverFactory

See merge request !453

getMatOrThrow handed out a reference to the underlying matrix, but for
the compiler it was undecidable, whether this might be a dangling
refernce. This lead to many warnings. We now hand out the
AssebledLinearOperator and call getmat explicitly where ever needed.

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