removed dead characters from the battle
slight cleanup. i was bothered by the constructor being in the middle of all of the properties and moved it to the top of the methods
changed how the CanMove property is adjusted to do it during ExecuteCommand, and to also rely on command.Character, rather than _selectedCharacter, since during the enemy's turn it may not be so clear cut if the _selectedCharacter is appropriate
locked out the attack ability after it has been used by a character during a round
prevented the player from selecting enemy characters
added button to end player turn