restore keyboard layout on vim exit

[lyokha]

restore keyboard layout on vim exit

[lyokha]

Hmm, a good point! It is not implemented but it's easy to do. Wait a minute...

[lyokha]

Try updated version.

[lyokha]

I'll leave it open because current implementation works well only in terminals (which is rarely needed in practice), but gvim has issues both in Linux and Windows (see comments to commit 1e5d4c9).

1. In Windows with global keyboard layout switching configuration it does not work for unknown reason.
2. In Linux there are confusing interactions with keyboard layout switching layers like xneur.

This issue requires further investigations for gvim. In any cases the feature is not required at all when the system keyboard layout switcher is configured on per-window basis.