Root safety-checking

Fixes #9117.  Thanks to Rivet and  Kyriolexical Dino for reporting.
Express safety-lock

As requested.
Saprophage fixes

Because you're gonna be a while waiting for your clean water to rot.  XD
Refactor game::throw_item
Fixes some stupidity I made
Comments
Nitpicking on math
Merge pull request #9118 from KA101/soilfocus

Root safety-checking
Merge pull request #9131 from EpicOrange/upgrade-code

Moved around code in game::throw_item
Make sure pointers are initialized.