Mainline tracking

[LambdaSix]

Updates required for new Nested Container PR:

• [ ] Convert CONTAINER to GENERIC for water-storage vessels
• [ ] Rework storage items to new pocket_data format
• [ ] Take opportunity to introduce aspects of #73 and #66 as possible.
• [ ] Refactor for bullet_resist changes to materials
• [ ] Play-testing above changes

[LambdaSix]

As experimental builds are now stable(ish), this can be packaged up into a 0.4E (experimental) build for release when I have time.