Add ElytraAttitudeControl module

[IceTank]

Adds Attitude control for elytra flying

Key features:

• Fly at a specified altitude by controlling pitch
• Fly at a specified speed by controlling pitch
• Automatically use fireworks when speed or altitude drops
• Features a PID controller for a smooth generalized pitch control
• Has a pitch40 mode to gain height so you can fly indefinitely

[IceTank]

Still have to work a bit on the firework usage. I don't think it works right now.
Works now