redesign of the user interface

Hugin's user interface has grown historically, and often by accretion. The result, and the workflow that it implies by it's layout, can at times be unintuitive and feel awkward. There is a tendency to represent entities in the code even if they don't naturally translate into common image processing or accepted software use concepts. This tendency is understandable, since hugin started out as a user interface for a set of command line programs, but by now the underlying flow of control matters little to many users, and the command line programs' iconography is alien to them. The the UI needs an overhaul with a focus on usability, streamlining common tasks, lowering the threshold for new users, and yet providing efficient access to advanced features for power users. Ideally this process would encompass the whole program rather than tackling individual bits, and it should result in a user interface that's clean, coherent, efficient, intuitive and elegant.