fixed GMRes

removed bool recalc_defect
reimplement the update function with respect to optimality
fixed strange behaviour when maxiter is reached and GMRes wants to restart infinitely many times
fixed strange behaviour when linear reduction is reached but GMRes wants to restart and continue calculation
fixed the printing of the results
fixed MinRes with the following changes:

replaced the usual arrays for the Givens-rotation coefficients and the search directions etc. with the arrays from Dune

implemented the BLAS-routine drotg for greater robustness which was a TODO note to compute the Givens rotation
changed the initialization of the arrays in the MinRes solver to remove the compiler warnings
added the old constructors called with the variable recalc_defect to RestartedGMResSolver and set them as deprecated, since they should not be used anymore
made the distinction between field_type and real_type which is the same for real numbers but differs for std::complex
[GMRes] Fix deprecation warning for old constructors

Function attribute have to be placed in front of the function name,
not behind it.
Merge branch 'feature/fix-gmres-and-minres'

* feature/fix-gmres-and-minres:
  [GMRes] Fix deprecation warning for old constructors
  made the distinction between field_type and real_type which is the same for real numbers but differs for std::complex
  added the old constructors called with the variable recalc_defect to RestartedGMResSolver and set them as deprecated, since they should not be used anymore
  changed the initialization of the arrays in the MinRes solver to remove the compiler warnings
  fixed MinRes with the following changes:
  fixed GMRes

Conflicts:
	dune/istl/solvers.hh