Special keys in config should follow similiar syntax to that used in
vim:

left arrow = `<Left>`
right arrow = `<Right>`
page down = `<Page down>`
home = `<Home>`
esc = `<Esc>`
F4 = `<F4>`
Ctrl+s = `<C-s>`
Meta+k = `<M-k>`

Examples:
=========

```ini
[column_keymap]
<Left> = prev_column
<Right> = next_column
<Esc>k = home
<C-s> = tag {} foo 1
<M-s> = tag {} foo
```