Update dependencies & examples to glutin 0.9 / winit 0.7

[alexheretic]

This PR brings gfx up to date with the latest glutin & winit releases. Having a ContextBuilder in addition to the WindowBuilder and a rework of the event structures are the main changes for gfx users. The events are particularly groansome for refactoring. I'm particularly interested in getting gfx up to date so I can finally have XWayland window support in Linux. See glutin ContextBuilder addition PR & winit event rework PR

Fixes #1348

[brendanzab]

Updated the description so that #1348 will auto-close.

[alexheretic]

I've amended the commit to fix Vulkan compile issue, and apply the same fixes to mac/windows. I couldn't actually test these though.

[kvark]

Amazing work, thank you!
Just one question/concern before we proceed.

[kvark]

any reason the poll_events blocks are rewritten? is it rustfmt doing the work?

[alexheretic]

Code had to be reworked to handle the winit::Event rework. Events seem to be split into Device & Window now, plus in general all winit events are more nested and have switched to named variable enums.

I've simply reworked the existing code into the new structure.

[mitchmindtree]

@alexheretic you might have already addressed this somewhere else, but I couldn't find it in this PR so just in case I wanted to add that GlContext::resize must be called now when either EventsLoop::poll_events or EventsLoop::run_forever receives Resized events, e.g. see here for a demonstration in the updated glutin example. This is because the glutin::Context does not know about events being emitted by the eventloop, and on some platforms (macos comes to mind) GL contexts require being updated when the window is resized.

Originally this was not necessary as glutin wrapped the entire EventsLoop and so this could be hidden from the glutin user.

[alexheretic]

Thanks @mitchmindtree, nice spot. Not ideal from a consumers perspective. I'll raise a PR to fix the examples.