- The <Hyper> key now sends <C-M-S-Insert> to make keybinding
  easier.

- the <Ctrl> key with a multibyte character now prepends
  <C-M-S-Insert>

- <Shift-Space> now returns the "\x1b[32;2u"

- <Shift-Alt> now sends ""\x1b\x1b[32;2u""

To make it possible to detect the replacement of the configuration file
when it is a symlink, the symlinks path has to be observed in addition
to the canonicalized path. That way changes to either file will trigger
a live config reload.

Multiple layers of symlinks would still not get detected when any
symlink other than the configuration file itself is replaced, but this
patch should cover most realistic usage scenarios.

During the deprecation of the 'background_opacity' field, it was
incorrectly renamed to 'window_opacity'. This changes that back to ensure
the old field still works and a warning is emitted accordingly.

See the original regression here:
https://github.com/alacritty/alacritty/commit/c24d7dfd0d2d8849f0398d7cb1a65d6562ee7a0d#diff-f92f0b1ad70a7b75b7266f3c9e569025e023d186814aa88c2b690800850ccb78L72-R73

Fixes #5437.

While structopt also uses clap under the hood, the configuration through
annotations allows for significantly more maintainable and concise CLI
definition.

This will also make it far easier to have platform-specific options,
which is problematic with clap since no individual methods can be
removed from its builder.

The change in Alacritty's CLI has been kept to a minimum with the only
significant changes being the `--version` flag listed before the
`-v` flag and the authors all on the same line.

In some cases it could be desired to apply 'background_opacity'
to all background colors instead of just 'colors.primary.background',
thus adding an 'colors.opaque_background_colors' option to control that.

Fixes #741.

Fixes #4132.

This bug comes from 530de00049c2afcc562d36ccdb3e6afa2fe396a5. The vi
cursor movement changes text selection range when it is on vi mode. On
the other hand the cursor movement doesn't change the range when it
isn't on vi mode. So preserve text selection range by toggling vi mode
early.