More release prep stuff.

Updated readme/cargo to v0.2.

Fixed font rendering when using some font sizes.

make rsx macro return the root entity

Implemented grid layout style props

Fixed texture atlas messed up from DPI.

fix sdf AA for sub-pixel text rendering

Marginally improved the main menu example.

Added settings to turn on/off subpixel rendering.

subpixel text rendering

Added computed styles. Breaking change!

- Widget's with styles must also include a ComputedStyles component and set it to equal to your styles object.

Export the cursor types.

Fixed issue where wasm fails to build.

Native msdf

Update link to font chapter

It was a link to `chapter_5.md`, which is chapter 4. I changed it to `chapter_6.md`.