GUI-379: Reinstate tags filter in image picker on launch instance and launch config wizards.  Prevent enter key from submitting form when an image id is entered or when the tags filter field has focus.
GUI-379: Return a friendly 404 not found page when the image id search fails to return a result in the launch instance and launch config wizards.
Merge pull request #406 from eucalyptus/GUI-379

GUI-379: Enable tags filter for image picker in launch instance and launch config wizards