Database parameter <easyrpg_immune_states> cannot immune to states with a lower ID, and causes a crash upon battle game over if Death is immuned to itself

[Mimigris]

The database parameter <easyrpg_immune_states> allows to define a state to be immuned to other states, by using a true-false array (e.g. F F T to make a state be immune to state 3 and state 3 only).
If you have a state, and that said state is immuned to another, you will not be able to get the other state.
If you have a state, and that you get another state that is immuned to your current state, your current state will be cured.
If a state is set to be immuned to its own ID, the state will not be possible to get.

• The immune property currently does not seem to work if it is applied on a state that has a lower ID than the state that has the immunity property (e.g. if state 3 has the immune property set to F T, which should immune it to state 2, this does not seem to work).
• If the state of ID 1 dedicated to the Death state is set to be immuned to itself, the game will be able to run fine, with just heroes getting to 0 HP without having a Death state, but during a battle, if all of your party gets to 0 HP, the Player will crash.