The glutin 0.30.0 update decouples glutin from winit which
provides us with basis for a multithreaded renderer. This
also improves robustness of our configuration picking,
context creation, and surface handling.
As an example we're now able to start on systems without a vsync,
we don't try to build lots of contexts to check if some config works,
and so on.
That also brings us possibility to handle context losses, but that's
a future work.
Fixes#1268.
This patch adds a new mechanism for changing configuration options
without editing the configuration file, by sending options to running
instances through `alacritty msg`.
Each window will load Alacritty's configuration file by default and then
accept IPC messages for config updates using the `alacritty msg config`
subcommand. By default all windows will be updated, individual windows
can be addressed using `alacritty msg config --window-id
"$ALACRITTY_WINDOW_ID"`.
Each option will replace the config's current value and cannot be reset
until Alacritty is restarted or the option is overwritten with a new
value.
Configuration options are passed in the format `field.subfield=value`,
where `value` is interpreted as yaml.
Closes#472.
