Need to get info about window state (maybe only on Windows)

Need to add possibility emit Maximized and Minimized window events to winit.
Current implementation on window minimizing only sends Resized event, where window size on Windows machines equals to zero (w = 0, h = 0). Sometimes it causes bugs in programs (like games), where aspect ratio dynamically calculated on window size change.

There are two suggestions to implement:

• Add completely new window events - WindowEvent::Minimized and WindowEvent::Maximized, as the result of window minimization don't send WindowEvent::Resized, only that two new
• Update current WindowEvent::Resized(u32, u32) signature to a new WindowEvent::Resized(u32, u32, bool) one, where bool parameter will be a window minized (true)/maximized (false) state

Look at the following PR's:

• https://github.com/kvark/three-rs/pull/42
• https://github.com/ozkriff/zoc/pull/244

Start by reviewing the two referenced pull requests and compare their approaches to reporting minimized and maximized window state. Decide which event API and platform behavior the project should support; done means the chosen behavior is implemented consistently without causing incorrect resize-based aspect-ratio calculations.