Initial progress on Images landing page.  GUI-56

Restrict AWS image fetches to images owned by ‘self’, Amazon AMIs or AWS Marketplace images for now.
Pass the owner_alias filter to the JSON landing page view, since we’re filtering server-side now.
Add convenience property to master layout to build more reliable tableview/gridview URLs that don’t lose the URL query string args.
Modify landing page filter to do case-insensitive matches on configured filter keys.
Use namedtuple for filter choice container.  Better styling for ellipses overflow when image description is too long in tile view.  GUI-56
Add “Launch instance” button to each image on landing page.  Stub out Launch instance page.  Minor visual tweaks to landing pages styles.
Merge pull request #13 from eucalyptus/GUI-56

GUI-56: Images landing page