Whitespace cleanup

[larsimmisch]

This is a global cleanup of trailing whitespace to avoid spurious whitespace conflicts in the future.

(I ended up using Visual Studio Code and did a global regex replace +\n -> \n. Looking at https://github.com/larsimmisch/pyalsaaudio/pull/145/files?diff=unified&w=1 shows up empty)

[ossilator]

looks about right, but please wrap the commit message body to 72 columns (like plain-text email), see https://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html