Properly forward constructor to CopyOrReference members.

3 jobs for feature/proper-generic-copyOrReference-in-BoxConstrainedQuadraticFunctional in 5 minutes and 42 seconds (queued for 1 second)
Status Name Job ID Coverage
  Test
passed dune:git clang C++17 #29046

00:05:42

passed dune:git gcc-6 C++14 #29048

00:04:05

passed dune:git gcc-8 C++17 #29047

00:05:12