JCLOUDS-331 - support specifying an imageChooser function in TemplateBuilder
Trivial: Remove unnecessary for loop in Atmos signing
Fix OpenStack Nova SecurityGroupExtension based on live tests

So there were a few problems, but the core ugly one is that what you
pass in for creating a rule allowing groups' access is not the same
thing you get back from a group with such a rule, which makes mapping
between the arguments and the output insanely painful. So now, well,
we do some insanely painful stuff.