Fix warnings about "unused" parameters and typedefs.

CLang and recent GCC warn about the "typedef" 'OneColInt' in
AutoDiffHelpers.hpp being unused.  Similarly, GCC warns about unused
parameters in various place at level "-Wunused".  This change-set
either removes ('OneColInt') or suppresses those messages.
Merge pull request #37 from bska/Wunused

Fix warnings about "unused" parameters and typedefs.
Merge branch 'master' of github.com:bska/opm-autodiff into eigen-3.2
Fix boundary condition checking bug.
Merge pull request #39 from atgeirr/master

Fix boundary condition checking bug.
Guard against null-pointer dereference.

This restores the check that was lost in commit 79562ca.
Merge pull request #40 from bska/nullptr-deref

Guard against null-pointer dereference.
Merge branch 'master' of github.com:bska/opm-autodiff into eigen-3.2