Better shopping cart movenent. It will now be dragged behind the player.

TODO: Check if this works with bigger vehicles as well.
First pass.
Water purification tablets!

Rather rare and incredibly valuable!
Production methods.
More production.
Charcoal water purifier.
Item spawns.
Recipe diversification.
Better recipe.
Changed quantity.

Enough to clean one gallon.
Plus nothing holds five units of water.
Adding matches to recipe.
Adjusted rarity.
Altered charcoal purifier efficiency.
Char creation: Profession scrollbar fix.
Add an information message when you start studying a book to tell you how to stop. Addresses #1505.
item: ensure the same default initializers are applied for all constructors as well as item:make. Fixes 'charges' leak in mapbuffer::load
Might as well increment savegame_version since save compatibility was busted
since the 1st. Also, made a global variable
First pass.
Balancing.
Recipe simplification.