Feature merge from development version. Changes include:

• Support for experimental ports directory.
• Support for patches to be applied automatically.
• Acknowledge that we're currently testing 2.7, not 2.8.
• Various formatting and string tweaks.
• Use a slightly better logic for clearing out stale patches.
• Work around 4-STABLE's default pkg_add weirdnesses.
• Add a mechanism to skip running cvsup.
• 4-STABLE caveat tweaks.