It is important to define the buffer local backend variables
in a config.el otherwise it is not available in the layer
configuration if the auto-completion layer is removed.
There were also some issues by hiding the explicit
configuration of company inside a macro, for instance
helm-spacemacs is unable to display the company package
configured in a given layer if the auto-completion layer
is removed.
Now in addition to the <layer>/init-<pkg> function there are
- <layer>/pre-init-<pkg> (executed before <layer>/init-<pkg>)
- <layer>/post-init-<pkg> (executed after <layer>/init-<pkg>)
The init function is mandatory, if it is not present then the
package is ignored and not installed.
This mechanism allows soft (implicit) cross layers dependencies
between packages (see company for more info).
It is now possible to remove flycheck from spacemacs layer and
move it to its own syntax-checking layer.
