add missing item, prep new content mechanics

- added items to content that were previously only referenced in Store
     >wood, cloth, meat, leather, etc
     
- changed Buildings and Upgrade to have req (requirements) and getReq
  instead of cost, getCost

- changed Items to have trade, getTrade instead of cost, getCost

none of the changes have been implemented outside of Content, meaning
game cannot currently function at all
restructure file system

restructured the file system for better organization
move item weights from Path to Content

Got rid of weight information in path, instead items in content now have
a weight property. All references to Path.Weight should have been
corrected to refer to the item.weight itself.
added Content.allItemsList

this list is meant to keep track of all items for non-type-specific
checks, meaning each list won't need to be checked with if/else chains
fix item list checks to refer to allItemsList, add charm

fixed if/else calls to item and weapon list to single allItem check

added the charm to content list
move path.js and ship.js to location folder