Item -> Msg

Forget items: too mainstream
CODE REVAMP

ONLY STATING MAIN CHANGES:
-Added global static array that will contain info on each and every user
-Forget the “Node” node system; welcome “Users” struct
-“Message” doesn’t need “to” integer
-Removed all those useless macros
-Added (and corrected other) prototypes
-No more “Items”, just “Messages” or variants of the name
-Organized the code a bit

CODE STILL NEEDS TO BE FINISHED REWRITING