Held key when game loses focus

[Apostolique]

When a key is held and the game loses focus (IsActive becomes false), it's possible for the player to let go of that key. When that happens the Released() condition doesn't fire. It might be useful to consider the focus loss to be the same as letting go of the key.

[Apostolique]

There's another case to consider. When clicking away from the window, that click will trigger Held(). The fix should be the same as what's done in Pressed() with IsMouseValid.