merge: upstream changes

 * Fix raw socket read/write to follow expected behavior
 * Fix truncation of long filenames in attachments
 * Add $include_encrypted config to prevent reply-decryption attack
 * Use gpgme recipient strings for encryption when available
 * Fix mailcap %{charset} expansion in send mode
 * Check noconv for mailcap %{charset} send mode expansion
 * Expand a couple of the comments about charset
 * Add "Message Composition Flow" section to manual
 * Minor buffer handling code cleanup
 * Improve imap uid seqset hcache buffer usage
 * Fix imap_pretty_mailbox() call to url_ciss_tostring()
 * Add mutt_buffer_expand_path()
 * Fixes to mutt_buffer_expand_path()
 * Add mutt_buffer_strcpy_n()
 * Add mutt_getcwd()
 * Add documentation on thread tree characters and config vars
 * Fail oauth quietly if it was not configured
 * Change IMAP to try oauthbearer first
 * Remove h->active hack in imap_sync_message_for_copy()
 * Restore active flag in imap_fetch_message() on error
 * Add a note about spam and the header cache in the manual