ChangeScreen2: Add reviewed checkboxes to the files table

To the left of each path display a checkbox that indicates if
the file has been marked as reviewed by the user. Toggling the
state of the checkbox updates the reviewed flag for the file.

To acquire the reviewed flags in bulk for a revision the /files/
collection has been modified to accept a "reviewed" query parameter.

Change-Id: I306ba919060b89f162885159e46e20253aad2db2
5 files changed