Guadec Update

Edward and I worked out the following todolist for me:

1. (done) Fix file load/save support
   
2. (done) Multiselection in advanced UI
3. Layout changes
4. Resize clips in advanced UI
   
5. Deleting in advanced UI
6. Split clips in advanced UI
   
7. Multi-selection Dragging
8. Time-stretching of clips

As you can see, the first two items are done. The next step is to make some layout changes to the advanced UI to allow for tools, such as a cutting razor, shifting of sources, what have you. The first tool will be a delete button, which will delete everything in the current selection. Then, I'd like to have a trimming razor which will split the cursor at the mouse position (some kind of floating bar will show where the source will actually be trimmed, an alternative would be to trim at the current playback head position).

Meanwhile, Edward is working on adding still picture support in PiTiVi core.

1. The first step is a bit of refactoring to move useful code into more abstract classes.
   
2. A custom freeze-frame element will be created for actually handling still pictures within a timeline.
   
3. This will be used to implement a TimelineImageSource object in PiTiVi core.
   
4. Finally, changes to the discoverer will be necessary to avoid long delays when importing large images.

So, by the time the PiTiVi backend can handle images, the ComplexTimeline should be a lot more functional. And, finally, you can actually save your work.