This replaces all of the Apache blurbs at the start of each file with an
`# SPDX-License-Identifier: Apache-2.0` string. It also fixes existing
uses to be consistent in capitalization, and to be placed above any
copyright notices.
This removes nearly 3000 lines of boilerplate from the project (only
python files), which no developer cares to look at.
SPDX is in common use, particularly in the Linux kernel, and is the
recommended format for Meson's own `project(license: )` field
These are only used for type checking, so don't bother importing them at
runtime.
Generally add future annotations at the same time, to make sure that
existing uses of these imports don't need to be quoted.
Dylan Baker
Eli Schwartz
Daniel Mensinger