Adjustable difficulty setting

I think this game needs some difficulty settings, that allows you to change gameplay experience.

Some options could be:

[x] Allow/Disallow Airplane capture missions
[x] Enable steady resource flow while standing to a faction is at 25%; 50%; 75; 100% (to discourage faction raiding)
[x] Slider for Evolution speed
[x] Enable aggressive Faction war, faction are more likely to attack each other
[x] Slider for Density of enemies in missions (Enemy credits)
[x] Slider for SP gain per Soldier Level (10; 20 (standard); 30)
[x] Slider for SP gain per Mission (0; 5; 8; 10)
[x] Enable/disable Science steal mission
[x] Enable resettling of destructed havens (some kind of endless game mode)