Until now, the "vertex group" limit method in the modifier
only worked for "vertex only" bevels. With this change,
edges with both ends in a vertex group will be beveled
in the non-"vertex only" case.
Also changed the test for being in a vertex group from
"any nonzero weight" to "weight >= 0.5". This is because
cascaded bevels on disjoint vertex groups did not give
disjoint bevels, because weight interpolation would give
non-zero weights to newly created vertices in earlier bevels.
Chose 0.5 because that won't result from interpolation, but
still allows some dilution (e.g., cascaded bevels on the
same vertex group).
2a8f6e2fd9