Clay And Pottery pack. Part 1.

Construction options:
1. Cut Down Grass
2. Remove Dirt Mound
3. Extract Clay Mound
Items:
1. Clay jug
2. Clay bowl
3. Clay container
4. Clay canister
5. Clay pot
6. Clay quern
7. Clay teapot
8. Clay lump
9. Brick
New materials:
1. Fresh Clay
2. Clay
New terrain object:
1. Clay mound
Remove unneeded space.
Change clay mound.
Remove flags from clay bowl.
Change clay vessels recipes.
Merge remote-tracking branch 'origin/master' into vehref
Made the rest of the booze feed fire, separated it. Added booze, flesh to incendiary case.
Give all matching names equal odds
Replace vector copying with lookup
Const accessors in preperation for more const changes.
Use auto and existing map methods to reduce reliance on i_at() returning a non-const vector.
Add i_at_mutable() for code that needs direct access to map item lists.
Add accessors to safely access items on the map.
Make map::add_item() public to bypass certain checks when necessary.
Split handling of map items and vehicle items so map items can be handled more safely.
The payoff, make map::i_at() const to reduce risk of bypassing caching.
Reorder charging station checks for slightly better performance.
Fix lua accesses of items.
Small mapgen fix
Adds option to disable new invlets (except manual)