Representation of keyboard shortcuts

We need to decide how keyboard shortcuts should be displayed to the user. We should also add this to the HIG and keep it consistent across apps, to avoid confusing users. The main questions are:

- Which keys should be represented by a symbol, rather than their name?

[Modifiers]
Super: ⌘ (⊞ Windows logo, just kidding)
Shift: ⇧
Alt: ⎇ (or Apple's option key: ⌥)
Control: ^ (or Ctrl or ⎈ (yes, that's the Unicode symbol for control))

[Non-Modifiers]
Tab: ↹
Arrows: ←↓→↑
Enter: ↵

- What separator should be used?

'', '+', ' ', ' + ', '-', (or maybe '·'?)

- How should the modifier keys be ordered?

Gtk currently provides a function for converting shortcuts to a readable form, but the output isn't really clean, e.g. 'Shift+Super+Right'

some suggestions:

⌘W
⌘ W
⌘+W
⌘ + W
⌘·W

^C
Control+C
Ctrl+C
Ctrl·C

⌘→
⌘·→