Bugfix/geneo test arpackpp requirement
testgeneo.cc until now was compiled once ARPACK was found, however we need ARPACKPP.
@dominic I'm not entirely sure about FindARPACKPP.cmake, does ARPACKPP_FOUND imply ARPACK_FOUND? (We need both for geneo to run)
Also, removed ARPACK requirement from TwoLevelOverlappingAdditiveSchwarz which supports any basis type (including not eigenproblem based ones).
Fixes #110 (closed)
Edited by Steffen Müthing