I placed this in "addons" since the "save actions" is not in the category list yet (or I should drink more coffee...)
Anyway, I'm using this plugin with a setting of saving every 10 seconds. I also have enabled the option "strip trailing spaces upon save" in the addons.
This combination produces some quite annoying side effects -- it often saves right after I pressed space or return, making the space or the current indentation level disappear.
I would love to see an option "skip stripping space on current line upon auto-saving", or even make this default behaviour.