This fixes commit 1cd2bb99, which attempted to plug the memory leak due
to unfreed MPI communicators.

yet another attempt to improve single/double and real/complex
unification more readable

with obvious meaning

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

This is immensely helpful to diagnose out-of-bounds accesses and memory
leaks.

The MPI communicators were never freed, this created a memory leak for
every elpa_allocate()/elpa_deallocate() cycle.

The were a couple of places where a load of a stack variable was too
wide. Detected with the

  -fsanitize=address

flag of GCC, that we should probably incorporate into our CI tests.

Anything if it makes Andreas happy :)

The timer object was not properly removed when elpa_destroy() was called
on an ELPA instance, leading to a memory leak

Previously you could set up ELPA with nev > na and force a crash.