This took much longer to get out than I had planned, but 0.9 is finally out.
The main change is the addition of a
mod merging system by PeridexisErrant. This also affects graphics pack installation somewhat, so I recommend keeping a backup and doing some additional tests.
A new requirement is the presence of an unmodified vanilla Dwarf Fortress installation in the folder LNP/Baselines, in order to give the merging logic a known base to work off. If you do not provide this, PyLNP will automatically download it if the user accepts this (either through a confirmation dialog or by opting in to all auto-downloads using File > Allow auto-download of baselines). For simplicity in code, it will always download the Windows version; this is perfectly fine even on Linux or OS X, since the binaries are not used for anything and will be removed after download any way.
As a precaution in case this change causes too many issues and needs to be rolled back, there will be a temporary freeze on any and all work unrelated to this new system - bug reports, feature requests, etc. are still welcome, but I won't be working on them while this is ongoing. After more people have had a chance to try it out, "ordinary" commits will be OK once again - exactly when this happens depends on how soon pack authors update, but I'm expecting 1-2 weeks from now.
I've asked PeridexisErrant to make a post here with any additional details he feels are important to point out, so that should happen once it becomes daytime for him.
The pull request containing these changes may also be helpful for additional documentation.