changed: update to be in line with upstream libert.ecl changes

this is the updates for ert. we had to do some changes for packaging

1) headers are not flat in $prefix/include but has their own subpaths. conflicting filenames such as menu.h
2) libs have more unique names to avoid conflicts (libgeometry.so is very general, so is libwell.so).

i don't know when upstream will merge it, but you can see the changes here; https://github.com/Ensembles/ert/commits/debian-package