TradeAgent will use hero power, smarter with buffs

Will still play an Abusive on an empty board and stuff like that. 

Squashed commit of the following:

commit d7407ff8bf79d0e894aa61caa16e38d94eea979a
Author: Mike Harris <mharris717@gmail.com>
Date:   Thu Sep 25 13:01:34 2014 -0400

    Less braindead buff/battlecry behavior

commit bc79e23a519298b0937f97c74d34ebd5ec009c68
Author: Mike Harris <mharris717@gmail.com>
Date:   Thu Sep 25 11:55:32 2014 -0400

    Added Hero Power usage

commit ce4e3aba109e999140c9ffb3e16f4b502ef9be8f
Author: Mike Harris <mharris717@gmail.com>
Date:   Wed Sep 24 12:30:54 2014 -0400

    marginally less stupid buffs, only for Abusive