CMake: add module for dune-localfunctions
add cmake modules to find ALUGrid and METIS
Finddune-grid.cmake: test for ALUGrid and METIS

ALUGrid is needed to avoid unresolved symbols if dune-grid was
compiled with it. METIS is used by the parallel version of
ALUGrid. (Although it is not open source...)
Add HAVE_CXA_DEMANGE config.h variable to Finddune-common.cmake

This will make Dune::classname usable on Dune master. (the 2.2 release
should be fine even without it.)
add cmake module to detect ewoms
make the FindALUGrid module compatible with the OPM build system
tweak the configure script

we should recognize the --with-{alugrid,metis} options...
FindALUGrid.cmake: incorperate Roland's comments to PR 317
Merge pull request #317 from andlaus/cmake_improvements

Cmake improvements