Keyboard shortcuts should check keyboardEvent.char, not keyboardEvent.code

[OptiverTimAll]

In #88, the keyboard shortcuts to promote and demote tabs were changed to Ctrl-Shift-comma and Ctrl-Shift-period. However, my keyboard uses the Dvorak layout, and those shortcuts don't work for me.

However, if I press Ctrl-Shift-V (V in the Dvorak layout is located where period is in QWERTY), the current tab is demoted. If I press Ctrl-Shift-W (W in the Dvorak layout is located where comma is in QWERTY), then Firefox prompts to close the entire window and all my tabs, because that's what Ctrl-Shift-W does in Firefox. Ctrl-Alt-Shift-F also does not focus the tab-search field, I need to press Ctrl-Alt-Shift-U (which conflicts with the Linux standard "enter a Unicode codepoint" shortcut).

If Tab Tree checked for keyboard shortcuts by character instead of keycode, they'd move around to match the current keyboard layout, like Firefox's built-in shortcuts do.

Customizable shortcuts (#49) would also be a good way to solve this problem.

[Fabiensk]

I second that: I cannot use these keyboard shortcuts in French layout ("azerty" and "bépo" layouts)

[Fabiensk]

Note: the shortcut " Control-Alt-Shift-f " (and maybe some others) does not work with French "bépo" layout on Windows: Firefox does not receive the flag for the Alt key for this combination. I don't see any way to fix this, excepted may modifying the bépo layout drivers… No problem on Linux.