start: enable trackpoint to work on Carbon X1
xsession: set X1 resolution to 1920x1080

HiDPI support is not quite here in Linux
keys: remap Carbon X1 keys

Well, many keys are missing. Let's try to recover the useful ones.

 1. Replace Esc by backquote/tilde. The escape key is at the wrong
    position. However, there is no other key to replace escape. So, we just
    don't bind it. There is only one shortcut using escape. I think I
    can live without it.
 2. Replace the previous backquote/tilde key (between alt and ctrl) by
    insert. I use this key for pasting into terminals.
 3. Replace both Home and End by Ctrl_L. It seems that End is hardly
    used. Maybe there is a way to replace it by something else.
keys: remove keyboard/mouse configuration to xorg.conf.d
keys: remove more keyboard/mouse configuration to xorg.conf.d
bindings: use Mod+Tab to switch to the previous tag

It was previously assigned to switch between two windows. I never used
it as is.
keys: use inputplug to configure keyboards
xsession: fix path to input event script