Prepare 0.17.0

[dhardy]

The CHANGELOG is long. Summary:

Significant additions include improved Input Method Editor (IME) support, font selection, font rendering (gamma correction and sub-pixel rendering support), several small input handling improvements, better resizing, a new text Editor component, revised image widgets Sprite and Image, a new kas-soft rendering backend and significantly revised view widget clerks.

Known issues: this release uses a pinned pre-release of winit which breaks AccessKit support.

I believe it is worth putting out this release despite the known issue since there have been a lot of changes since the last release.