[DICT] misc use cases

[Jeff Alexander]

I have added a new first column to the spreadsheet to capture our consensus priority for use cases. 

No one suggested the following should be treated as "musts", and the range of priorities proposed was narrow.  I have therefore assigned the following priorities based on the group's comments. 

#5: Two of you suggested this is a "nice to enable" rather than "should", and I am lowering the priority to reflect that. Also, this is not a very common type of dictionary.

#8 and 9: Most of you have suggested these be treated as one use case. I have marked both as "nice to enable", as the comments leaned that way overall. 

#16: I marked this as a midpoint priority, "nice to enable / should enable". That reflects some divergence of views. However, as this is not in the critical path, I think we can just table this for discussion at a later stage as needed.  

If you have any concerns on this, please voice them as soon as possible. Also note that we will not be spending any time on use case prioritization at the F2F on Sunday.