Improve Keyboard Controls

[viluon]

We need to fight input lag as fiercely as possible. The current system makes the player stay at one place if opposite movement keys (e.g. W and S) are held simultaneously. This might lead to disastrous situations when a key_up is dropped, and with higher input lag leads to confusion as the system has to catch up on the event queue. A system which responds to new input instantly - or at least as quickly as possible ("overriding" previously pressed keys) would really help. Additionally, we can also improve the controls by making them configurable and perhaps even add "click to approach," with proper pathfinding.

• Implement adjustable keybindings
• Switch to a better player movement system
• Implement mouse-controlled navigation