Proposal: Add v3dmm support

[jayrod246]

In order to close this issue, must implement:

• v3dmm movie open/save support. (.vmm files)
• v3dmm expansion management. (.vxp files)

Nice to have would be to not have to go through a manager at all when opening movies, the expansions needed are always bundled with the movie so just load them on the fly.

Also would be nice to not automatically install every expansion in a movie when opening. And with the built-in manager, the user could just choose which expansions from the movie they want to keep.

[plopilpy]

It would be nice if the v3dmm manager window could be opened as you use the program so you don't have to close the program to change settings or change a mod.

[jayrod246]

Yeah, that’s the idea is to have a manager built-in.