When updateNames() copies an image's record from a read-only store into
the read-write store, copy the accompanying data as well.
Add fields for setting data items at creation-time to LayerOptions,
ImageOptions, and ContainerOptions to make this easier for us and our
consumers.
Replace the store-specific Create() (and the one CreateWithFlags() and
Put()) with private create() and put() methods, since they're not
intended for consumption outside of this package, and add Flags to the
options structures we pass into those methods. In create() methods,
make copies of those passed-in options structures before modifying any
of their contents.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>