Convert class buttons/changeclass buttons/etc system

[chaseoes]

Change class buttons, changeclass buttons, etc. to use the same system as class chests: just look at the button when you type the command, without needing to type it then place the button.

Affected stuff:

• [ ] Class buttons.
• [ ] Change class buttons.

Resources:

• https://github.com/chaseoes/TF2/blob/master/src/main/java/com/chaseoes/tf2/commands/CreateCommand.java#L118

@psycowithespn is assigned.

[chaseoes]

@psycowithespn Progress?