What we print and how we print it are orthogonal options, so --format
shouldn't change what messages are printed.
notmuch command-line tool
-------------------------
+Fix the --format=json option to not imply --entire-thread.
+
Implement "notmuch search --exclude-threads=<search-terms>" to allow
for excluding muted threads, (and any other negative, thread-based
filtering that the user wants to do).