core: fix calls to `domish.Element.elements`: domish.Element.elements should be called with namespace and element name as 2 arguments, but it has been confused in several places with the call to `domish.Element.addElement` which is often done with a `(namespace, name)` tuple. Unfortunately calling with a tuple is accepted and doesn't raise any error in `elements`, but this result in a wrong element returned. This patch fixes the erroneous calls.

include MANIFEST.in sat/VERSION
global-include *.py
global-include *.ini
global-include *.po *.mo
global-include CHANGELOG COPYING* INSTALL README*
global-include *.sh
global-include *.yml *.yaml
global-include Makefile *.rst *.bat
graft misc
graft doc
include sat_frontends/jp/jp sat_frontends/primitivus/primitivus
include sat/bridge/bridge_constructor
global-exclude *.un~
prune sat/bridge/bridge_constructor/generated