Update Mixin to 0.6.6-SNAPSHOT
Update Mixin to 0.6.6-SNAPSHOT

Grinch/SpongeCommon,sanman00/SpongeCommon,JBYoshi/SpongeCommon,SpongePowered/Sponge,SpongePowered/Sponge,JBYoshi/SpongeCommon,SpongePowered/Sponge,SpongePowered/SpongeCommon,sanman00/SpongeCommon,Grinch/SpongeCommon,SpongePowered/SpongeCommon