Fix bugs in insertion logic

Don't expand aliases

Fix bugs in history search

Increase the default minimum delay

Suppress a warning

Fixes marlonrichert#357.

Make the tests compatible with `zsh` 5.4.2

Remove `_gnu_generic` usage

Fixes marlonrichert#318 and possibly marlonrichert#322.

Fix a deadlock in async completion

Fixes marlonrichert#298.

Don't use `$SHELL` in the test

…because that's the login shell, not the current shell.

Fix XDG base dirs handling

Fixes issue marlonrichert#262.