[Opm] Renaming dune-cornerpoint -> opm-grid

The repository has now been renamed on github. The old URL will still work for a long time (half a year I think) so no-one need to do anything right now. The next step is creating PRs with the required changes. This is underway. Atgeirr ___ Opm

[Opm] Oil-water-gas rates at perforation in simulators

Hi, I'm working on a better way of doing (Eclipse-compatible) output, and need to grab some info from the simulators. I have a WellState (and possibly Well* from opm-core) that I want to extract rates at some perforation. It seems to me that the perfRates in WellState only store the combined