#7 Add priorisation support

[Gilles Scokart]

The backlog prioritisation support is currently a little weak. It is possible to sort by the priority field, but it is not easy to adjust (if you edit the number, the table need to be redisplayed which kind of reshuffle the display).

Instead of ediing manually a number, it would be more convenient to have small arrows to increase/reduce or switch priorities of 2 item. An even easier way would be to have the possibility to drag a drop item in the backlog.

An other usefull help isto have a 'quick search' that highlight some item of the list based on some search criteria. This would allow to more easily reprioritize the highligted element.

When doing such reprioritisation, you might also find a way to use the dependencies between items (a popup, a visual barier or feedback that indicates the priorties doesn't match the dependencies. You could also automatically reprioritize the dependencies when required)