Updated the version from 1.1 to 1.2
Renamed the header to "Slint Royalty-free Desktop, Mobile, and Web Applications License"
Added definition of "Mobile Application" and grant of right
Moved "Limitations" to 3rd section and "License Conditions - Attributions" to 2nd section
Added flexibility to choose between showing "MadeWithSlint" as a dialog/splash screen or on a public webpage
Moved the para on copyright notices to section under "Limitations"
Achieve this by generating a `focus()` function for such components
and call it from the outside.
This replaces the previous focus handling with what should be cleaner:
- Any `forward-focus: some-element;` is basically syntactic sugar for
`public function focus() { some-element.focus(); }`.
- The init code gets simplified to calling focus() on the root, if it's
available.
Since the `focus()` functions are now generated in the imports pass,
they become visible in the style checker. That means the checker
requires consistent focus handling between the styles.
