[cmake] require + link tbb
init + use tbb(_assemble)
removes more legacy stuffs
thread-parallel localproblem solving
replace find tbb with better version
[cmake] find tbb gt moved to dune-stuff
fixes naming after dune-gdt/stuff changes
adds now-missing types in diff.eval traits
use nicer lambda in parallel problem solver
disable smp error calc for now
cleanup
fixes app inits
GdtSpaceType -> SpaceType
CommonTraits::DiscreteFunctionSpaceType -> CommonTraits::SpaceType

seemed reasonable since there's no non-discrete space anymore
MsFEMTraits::LocalGridDiscreteFunctionSpaceType -> LocalSpaceType
fix unnec. copies
fix viewRange deprecation + missing header
spaces are created as pointers
bunch of stuff is now not failing in threaded mode
makes error clac usable w. and w/o fem solution again