[SUGGESTION][GSTOOL] Hard-convert all sets to NeoLemmix resolution

[namida]

Differences in the implementation of resizing higher-res graphics have caused inconsistencies between versions, even if native-NL-resolution graphic sets work perfectly between both.

To avoid future issues of this kind, GSTool should hard-resize all graphic sets, rather than storing them at source resolution then having the player / editor resize them to NL resolution at runtime.

[namida]

Implemented for next update.