The root volume in a systemdisk setup is handled in a special
way. It is not allowed to setup a custom name or mountpoint for
the root volume. Therefore the size of the root volume can be
setup via the @root volume name. This check looks up the volume
setup and searches if there is a configuration for the '/'
mountpoint which would cause the image build to fail
Some attributes needed to be changed in the test xmls. With this
commit all the description files are consistent with the new co-
occurrence constraints.
Now each user item may or may not have a groups attribute. The
groups attribute is a comma separated list of group names. If
present the first group name will be the login or primary group,
if not present, the underlying toolchain will assign the default
login group for that user.
An instance of RuntimeChecker allows to semantically check for
error conditions according to the provided image description
and build options. Related to #20
