Partial Trapping moves now deal 1/8 damage

In Gen 5, partial trapping residual damage was 1/16 Max HP and 1/8 with
Binding Band
In Gen 6, it is now 1/8 Max HP and 1/6 with Binding Band
Merge pull request #418 from V4Victini/partialtrapping

Partial Trapping moves now deal 1/8 of Max HP for residual damage