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with obvious meaning

for easier comparisons of elpa and mkl, a test case using scalapack
function pdsyevd has been added

We got reports from a user that there were troubles with certain domain
decompositions. So far the tests only looked at (approximately) square
decompositions in column-major process order.

Now, a new class of tests loops over all possible decompositions
(row * col) for a given number of total tasks.

So far, we can not confirm that there are any problems, all
possibilities work as expected.

The module is intended to be hidden, thus I moved it into the public
part of the legacy API.

Some test programs use it, thus the test programs have now also access
to ELPA's private modules. This is of course anyway necessary to test
ELPA internals that are not exposed via the public API.

Introducing new test in which matrix and its eigendecomposition is
known and thus can be easily created and checked directly, without the
need to use scalapack or any other communication (apart from reducing
error).

The test is based on the fact, that if L_A and S_A are eigenvalues and
eigenvectors of matrix A, respectively, and L_B and S_B eigenvalues and
eigenvectors of B, then kron(L_A, L_B) and kron (S_A, S_B) are
eigenvalues and eigenvectors of kron(A, B).
Since it is easy to know exact eigendecomposition of a small matrix (e.g.
2x2), and kron operator has very simple structure, we can construct
arbitrarily large matrix and its eigendecomposition. We only have to
select small matrices such that the resulting matrix has unique and
ordered eigenvalues, so that the checking of the result is than easy.
Each element of matrix, eigenvector matrix and eigenvalue vector can
be quickly computed independently, just using its global coordinates.

The test is currently limited to matrices of size 2^n, but by
storing eigendecompositions of more small matrices (e.g. 3x3 and 5x5) we
could construct any matrix of size 2^n*3^m*5^o, which would probably be
sufficient, since most often used sizes (150, 1000, 5000, 2000, 60000)
are of this form.

The routines "eigenvalues" and "solve_tridiagonal" are now
also tested directly with the new API (and not only via the
legacy API -> new API mapping)

Todo: adapt test generator script to contain some logic

Most of the test programs for the new interface were all essentially
copy&pasted from test.F90, now all of those directly use test.F90 with
appropriate preprocessor flags