Make shops say "all" when all items are removed, fix info sign deletion
issue
Add netherbrickslab
Properly delete signs when they're removed.  Mark signs as broken when
they're not working.
Make transaction signs load much faster.
Fix transaction signs...
Rename /loaditems to /importnewitems
Add /importfromyml command
Catch updateHistorySign() errors
Don't display unnecessary loading messages.
Fix /importnewitems error message.
Remove brackets from /importfromyml warning message.