Merge pull request #18 from akva2/eigen3_fix_continuous_installs

fixed: workaround issues with ExternalProject_Add
fixed: autodiff depends on opm-core
Merge pull request #19 from akva2/opm_depends

fixed: autodiff depends on opm-core
autodiff: make it compatible with dunecontrol

the 'configure' script was missing...
check for the C++-2011 'auto' keyword.

It seems like the corresponding FindCXX11Features.cmake file
was not updated for this module.
make the c++-2011 feature set of GCC 4.4 mandatory

we now produce an error even if the module in question does not
actually use some of these features.