Todo

Editor:

[x] Add basic word motions like: w, W, e, E
[x] Add basic line motions like: $, ^, gg, G
[x] Add commands for normal mode: delete, change, yank
[x] Add commands for visual mode: delete, change, yank
[x] Add history: undo, redo
[ ] Add search in buffer
[ ] Add multi-cursor support (maybe)
[ ] Make keybindings configurable
[ ] Fix inconsistency between word motions and cursor movement

Problems:

- Cursor disappears at end of line.
- cw deletes current word + space + next word's first char.
    Got: <h>ello word" -> "<o>rld"
    Want: <h>ello word" -> "<> world"
- cb acts strangely
    - Got: "hell<o> word" -> "hell<e>llo world"
    - Want: "hell<o> word" -> "<>o world"
- dw current word + space + next word's first char.
    Got: "<h>ello word" -> "<o>rld"
    Want:  "<h>ello word" -> "<>o world"
- db acts strangely
    - Got: "hell<o> word" -> "hell<e>llo world"
    - Want: "hell<o> word" -> "hell<e>llo world"
- ce works as expected
- cE works as expected
- de works as expected
- dE works as expected