improved keybindings

- added support for single-shot types
- added 'onValue' and 'offValue' for single-shot and toggle (defaults to booleans)
- added support for keyDown handlers in the keyboard service's register function
accidentally switched single-shot and momentary

Now they are named correctly.
converted to new key bindings.
fixed a minor issue with handling of 0 values.
added support for using our actual turn rate.
Fixed paths so that textures are loaded correctly.
improved controls.