Rewrite smartshop to fix multiple issues

[fluxionary]

Smartshops have multiple issues. See https://github.com/fluxionary/minetest-smartshop for updates.

• [x] cleanup
• [x] investigate better ways to show shop contents w.r.t performance
• [x] log purchases
• [x] change color when shop is empty or has "money" in it (whatever the "pay" item is)
• [x] Get rid of the "line" as a separate inventory - make it just an indicator
• [x] auto-change minegeld
• [x] Fix wifi linking maximum distance (w/ configurable distance)
• [x] make expire_link expire only the correct link attempt (w/ configurable timeout)
• [x] fix wifi refill to not be insane
• [x] fix wifi send to move as much as possible to storage, not just 10 units of whatever
  • [ ] update shop status when wifi storage contents change
• [x] tubelib integration
• [ ] lurkcoin integration
  • [ ] purchase items using money in your lurkcoin account
  • [ ] send money received in shops to your lurkcoin account
• [ ] fix display of items
  • [x] fix display of nodes w/ complicated tiles
  • [ ] re-add the wield_item entity for mesh and nodebox nodes
  • [ ] add a new entity that is a composite of the 4 small entities when possible (there are image compositors for this)
• [ ] Ensure that the old smartshop mod can be updated to the new version with minimal issues, and document what they are.
• [ ] Shared mode - all players within a protection area get the owner interface
• [ ] Purchase log - see who bought what when

• [ ] Update README

  New bugs I've introduced that I need to fix:

• [x] comp players for items from the "give" and "pay" lines
• [x] wifi storage doesn't work @ negative coordinates :\
• [x] broken lurkcoin commit to master

[thomasrudin]

Will your rewrite be compatible to the old smartshops?

[fluxionary]

@thomasrudin I'm aiming for the ability to switch from the old mod to the new one with minimal issues. However, some things behave quite differently in the new version, and there (probably) will not be a way to go back without some serious effort. I also haven't tested the update process in a while, so I wouldn't recommend installing this version until I've finished the planned updates. I've put a note about checking the update process again at the end of the TODO list.

[thomasrudin]

Hey, no pressure :smile: we are currently on a stable commit of the smartshops anyway, no wifi storage and shenanigans yet...

I do have to test your fork though for compatiblity with my mapserver (https://github.com/minetest-tools/mapserver) The online shop-search displays also smarthops...