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"
Since commit 6fefe75a1c the handling
of forward-focus bindings happens before the resolve_expressions pass,
which means that we cannot rely on type mismatch
error handling yet.
Fixes#4475
