added configuration file for generation of code documentation using doxygen
restart of spectral solver is fixed and seem to work now also for restart at significant deformation.
spectral solver now gives exit code 2 if some increments did not converge
added information on itmin in output, impoved output
set exit code to 0 on successful termination (seems to be unix standard)
exit codes:
0: successful termination
1: error (using IO_error)
2: require regrid
updated the AL solver, still VERY experimental
Martin Diehl