test logging

• Testing: more logging to help debug a flaky test.

4.6.8: longer test timeout

• Testing: wait longer for scan_success_file_exists to avoid flaky timeouts.

4.6.7: groff 1.23 support

• add .metainfo.xml files for Appstream
• license name changed from "Expat" to "MIT" because Appstream doesn't recognize "Expat".
• fix nroff 1.23 warning about selecting font 'C', add a test for it

4.6.6: gcc 15 clean

• XtDestroyApplicationContext replaces XCloseDisplay, to stay at the Xt level.
• Callback and action proc types are now correct.
• mailbox-preview is included in the package description.
• pkgconf replaces old pkg-config build dependency.
• Testing: wait longer for scan_success_file_exists to avoid flaky timeouts.

4.6.5: nmh 1.8 support

• nmh 1.8 support (changes to unit tests only)

4.6.4: improved IMAP support

• Set window type to Notification so it doesn't steal the focus on popup.
• Expand internal buffer to handle multi-byte characters.
• Option -debug now takes a debug level.
• Handle unquoted literals in bodystructure response from IMAP server.
• Handle non-fuzzy preview from recent IMAP servers.
• Handle folded Subject lines.

4.6.3: disable automatic tests of window behavior

• Developers: Disable automatic runs of flaky windowing test.
  Test was introduced in version 4.5.4.

4.6.2: more robust test utilities

• Developers: Tests do not write soft failures to stderr

4.6.1: Maildir support

• Maildir format for local mailbox is supported by mailbox-preview.
• mailbox-preview has other minor improvements.
• Developers: Tests fixed to work without a merged /usr partition.

4.6: IMAP support

• mailbox-preview: new script to support IMAP
• scanCommand accepts a "rows" parameter with additional %d
• xlbiff.form moved to nmh's config directory and used by default