Motifs need to be creatable and editable from within the GUI

[diane]

I hacked in loading motifs from a file, but there really should be some kind of UI. This is closely related to handling of colors and other annotations in ticket:13.

Basically I do need to add/delete/select colors for motifs, but don't know if its part of the generic annotation code or specific code. But I just want to make sure it gets done.

[diane]

Implemented in [126].

Though motifs and annotations aren't particularly tightly attached.