Remove barrels from Cavalry mode

[madjsoh]

i dont think people realise the necessity of tomes and barrels at the moment past wave 16, ive beaten both marshal and queen there and its blatantly impossible to do without the use of these support items (unless the devs change things in the future) cav mode atm is terrible for exp and drops so its not like people are abusing the system by constant barrels/tomes. i say leave tomes and barrels in...especially tomes