Pigeonhole extensions and plugins

See Settings for list of all setting groups.

• Pigeonhole Sieve: Duplicate Extension
• Pigeonhole Sieve: Editheader Extension
• Pigeonhole Sieve: Extensions for Notifications
• Pigeonhole Sieve: Extprograms Plugin
• Pigeonhole: IMAPSieve plugin
• Pigeonhole Sieve: Include Extension
• Pigeonhole Sieve: Spamtest Extension
• Pigeonhole Sieve: Vacation Extension
• Pigeonhole Sieve: Variables Extension
• Pigeonhole Sieve: Virustest Extension