Add vim key bindings hjkl

[kencx]

Adds support for hjkl. Closes #2.

Fuzzy search mode is activated with / and deactivated with Esc. Changing directories also deactivates it.

For now, this is a breaking change. Making it configurable with export LLAMA_VIM_KEYBINDINGS=true seems to require multiple switch case statements, which is quite messy imo. Unless there is a better way?

Note: The git diff seems to have gone wonky after nesting the switch statement within an else.

[antonmedv]

Current mode should also be available.

[antonmedv]

which is quite messy imo.

So this is a challenge. Add feature and simply code.

[kencx]

Managed to implement configurable vim mode.

Any feedback is appreciated :)

[kencx]

Updated with the recent changes.

[antonmedv]

Done!