This is a bit cumbersome, as it involves yet another abstract
intermediate type, but necessary due to language limitations.

Setting a bandwdith of the input matrix via

elpa%set("bandwidth",bw)

tells ELPA 2stage, that matrix is already a banded matrix
with bandwidth bw. Then some compute steps can be skipped

We decided not to provide this information via the key/value store, but
rather to use the ftimings module for that.

@loh will take care to implement ftimings in the new API
@amarek wants to port the legacy API so that the old global module
  variables still contain valid values

Still missing is the compatibility layer, currently it only compiles
when configure is called with

  --disable-legacy

Also, a more general solution to parameter passing via environment
variables would be nice.

It could happen that ELPA stopped with an error but an exit code "0"
was given, i.e. one could assume everything was fine when it was not!
Now each Fortran "stop" was replaced with "stop 1" to prevent this

Due to a bug in the Intel compiler two stages could not be unified