Add biocoder & biodecoder.

• biocoder: add user's biocode to the item (cannot use on items which can be bonded, i.e. persona weapons, or have a biocode already).
• biodecoder: erase biocode or bond from the item.

Configurable:

1. add biocodability to all weapons/apparels (default: enable).
2. upgrade the item with quality when biocoding, and downgrade it when biodecoding (default: enable).

The combat supplier sells biocoders, and the exotic goods trader sells both of them.