Tag instance sooner

hey,

i've added some methods around tagging instance. now it mimics the current behavior,
but user can decide, whether to check for instance with the same `Name tag` before making
the instance, or creating it without any tag, or tag it even if this tag is already present.

there is also a property `tags`, that can be used for filling some more custom tags.

what do you think about this feature? of course, everything should be configurable
via cmd-line options and via profile. right now i am curious, whether you want to accept
this approach..

thanks.