Print elapsed runtime on unsteady solves

This is sometimes useful for optimization on nonlinear transient
problems
Merge pull request #16 from grinsfem/print_runtime

Print elapsed runtime on unsteady solves
Use @prefix@ for example config files

In combination with the @prefix@ that already preceded the executable,
this lets us run "out-of-source".
Merge pull request #17 from grinsfem/example_prefixes

Use @prefix@ for example config files