Physics Based Dragon Movement

[mnmaita]

Issue:

Closes #47

What was done:

• Added physics based player movement. It uses impulses to go forward and turn, and forces to make the dragon strafe a bit. It also has a "cruise" mode that makes the player "soft lock" to their current direction and bumps up the velocity. It kicks in when the cursor is within a certain angle of the dragon facing direction.
• Moved player movement code out of the input module.

[mnmaita]

Proximas iteraciones:

• Considerar aplicar fuerzas o impulsos cuando el jugador cambia la direccion abruptamente para transicionar mas facilmente.
• Considerar alterar alguna propiedad (centro de masa?) para hacer que el dragon gire menos sobre si mismo pero que vuele de forma mas curvilinea.
• Probar a fondo y ajustar valores de fuerzas, impulsos, escalares, etc.