Merge branch 'feature/make-test-depend-on-target' into 'master'

[cmake][dune_add_test] Set test property to depend on existence of target

Closes #100 (closed)

See merge request !404 (merged)

(cherry picked from commit 27af4005)

69efd0be [cmake][dune_add_test] Set test property to depend on existence of target

@joe can this be backported in 2.6?

merged

mentioned in commit 6ba9e6dc