Merge branch 'various-api-refactors'

diff --cc lib/sup.rb
Simple merge

diff --cc lib/sup/buffer.rb
Simple merge

diff --cc lib/sup/imap.rb
Simple merge

diff --cc lib/sup/maildir.rb
Simple merge

diff --cc lib/sup/modes/thread-view-mode.rb
Simple merge

diff --cc lib/sup/source.rb
Simple merge

diff --cc lib/sup/util.rb
Simple merge