Add yml validater to top.
Skip files unrelated to build.
Reformat comments.
Only build Release since Azure Pipelines already builds Debug and is faster.
Remove cmd since it's the default shell, and unneeded characters.
Don't trigger an AppVeyor build when .travis.yml is changed.
Removed - after | since it's unneeded.
Made %CONFIGURATION% lowercase to be consistent with actual env var.
Made after_build into on_success so artifacts aren't tried on build fail, and made Release check apply to all commands.
Made 7z archiving into one step since speed > cosmetics.
Removed empty space(s), and line at end of file.
