Add sort functionality to Updates/comments

[#1]

Allow updates/comments on projects, programs & requests to be sorted (by date, by user, by thread which is the current approach). Often users just want to see the most recent comments on a project. If folks are replying to an older thread, then the person cannot easily find the most recent updates.

[#2]

I really like the idea to sort by most recent comment so older threads come to the top when someone comments.