[buildsystem] merge from strip-pdelab: allow out-of-source builds, make

correct use of wildcards, add ALUGrid flags to tests with AMG.

Merge revisions 12949, 13246 and 13248 from the strip-pdelab branch.
They all improve the buildsystem behavior.

Thanks to Markus Blatt for the work.


git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@13282 2fb0f335-1f38-0410-981e-8018bf24f1b0