Fix continuation indentation, and whitespaces around operators.
This is just code reformatting, with no behaviour changes; no content
changed beside whitespaces, so "git diff -w" gives an empty diff.
Add or remove empty lines to match the needed ones around
blocks/functions/etc.
Adapt the generation of guestfs.py to emit the separating empty line
before adding a new function/alias, rather than after it.
This is just formatting, no behaviour changes.
