Restores the old twolevelmethodtest and adds a new one to test multithreaded
computation. Fixes the autotools build system to run the multithreaded tests
too. Furthermore introduces multithreaded test with superlu/umfpack.

This patch removed the tests for umfpack from dune-istl as they
are already needed in dune-common. There are modules using umfpack
that do not require dune-istl. Therefore dune-common seems to be the
more appropriate place for the test.

Dominic Kempf authored 11 years ago and Markus Blatt committed 11 years ago

This commit contains
- a wrapper for the C library UMFPack
- tests for both CMake and autotools to find UMFPack on the system
- a unit test for UMFPack
- a new MatrixType ColCompMatrix which is a base class for a column
  compressed matrix. SuperLUMatrix now inherits from this base class.
  This way, no code is duplicated for the very similar interface in
  UMFPack.
- the SuperLU-specific part of OverlappingSchwarz code is abstracted
  to work with either SuperLU or UMFPack

[[Imported from SVN: r1897]]

[[Imported from SVN: r1787]]

Thanks for the patch to Bård Skaflestad.

[[Imported from SVN: r1778]]

[[Imported from SVN: r1708]]

[[Imported from SVN: r1665]]

[[Imported from SVN: r1657]]

[[Imported from SVN: r1559]]

[[Imported from SVN: r1556]]

"DOUBLE"
to "SLU_DOUBLE".
Deprecated pre-2005 support of SuperLU.

[[Imported from SVN: r1527]]

[[Imported from SVN: r1526]]

[[Imported from SVN: r1525]]

to dune-istl.

[[Imported from SVN: r1524]]

[[Imported from SVN: r1492]]

[[Imported from SVN: r1281]]

The code was developed by Theo Aouidet, Stefan Bayha, and Dominik Ull
during their software internship at the IPVS in Stuttgart.

[[Imported from SVN: r1259]]

[[Imported from SVN: r1190]]

[[Imported from SVN: r977]]