dodoc: Add a QA warning when called with no arguments.

See bug #481664 and bug #480892.
Add test for bug #481628.
dep_zapdeps: prefer all_installed_slots choices

This will fix bug #480736, by preferring libpostproc in deps like
|| ( ffmpeg:0 libpostproc ) where libpostproc is already installed and
ffmpeg:0 is not.
repoman: --include-exp-profiles, bug #481326
repoman: fix manifest for --echangelog
SpawnProcess: add unshare_ipc and unshare_net