Make release event an opt-in feature

[TimonPost]

• Makes Event::Release and Event::Repeat an opt in rather then default enabled feature on windows and kitty. The motivation is that it isn't fully cross-platform and causes developers confusion when receiving two events unexpectedly.
• Fixes the issue where people got an Enter release event at application start up.

Fixes: #752

[TimonPost]

@lesleyrs you can potentially keep the pull requests open. Guess it might be cleaner anyways to have this explicit check for press events even if not enabling the feature introduced in this pr.

[lesleyrs]

@lesleyrs you can potentially keep the pull requests open. Guess it might be cleaner anyways to have this explicit check for press events even if not enabling the feature introduced in this pr.

Ok sounds good, I made it a mission to fix those libraries prior to this PR as the breakage was really quite bad for such a simple fix. But I'll try to get them merged still then.