Playtime: Handle SPACE even if set as global shortcut in REAPER

[helgoboss]

Pressing SPACE within Playtime by default starts just Playtime, not REAPER. This can be changed by setting the matrix transport synchronization from "Partial" to "Full".

However, many users seem to have turned SPACE into a global hotkey, making Playtime not aware of it being pressed. That means pressing SPACE always starts REAPER playback. That's bad. I should catch SPACE even if it's a global shortcut.

[helgoboss]

Need to postpone this until Justin came up with a way of knowing the pressed key in the hwnd_info handler.

[helgoboss]

There is a way to know the key now, passed into the hwnd_info hook. Thanks @justinfrankel!