[OpenMW] Handle groundcover plugins

[poperigby]

Groundcover plugins have a special entry in openmw.cfg like this:

groundcover=example.esp

The can't be enabled as regular plugins, or they won't work correctly.

[limo-app]

Since i do not play OpenMW myself, i lack experience with these plugin types. Am i right in assuming that there is no way to auto detect whether a plugin is a groundcover plugin using LOOT? If so, this would probably have to be handled by offering users the option to tag plugins as groundcover.

[poperigby]

Yeah, there's no way to tell whether a plugin is supposed to be used for groundcover. It's kind of a nasty situation, but there are plans to do away with groundcover plugins in the future and just use mesh flags.

For now, an option to flag them would be helpful.

[limo-app]

7e184ac added an option to flag plugins as groundcover, among other changes. See my post in #95 (comment)