FAQ: Common problem with Debian is not running update-guestfs-appliance.
FAQ: Tips about using direct backend and fixed appliance on Fedora/RHEL.
resize: Mark isatty function as "noalloc".

This turns it into an ordinary C call without the unnecessary [in this
case] GC frame overhead.  See:
http://camltastic.blogspot.co.uk/2008/08/tip-calling-c-functions-directly-with.html
resize: Mark progress bar functions as "noalloc".

Avoids GC overhead and turns these into simple C calls.  See:
http://camltastic.blogspot.co.uk/2008/08/tip-calling-c-functions-directly-with.html
sysprep: Various code refactorings of the operations.

 - Use 'op' instead of 'xxx_op' for operation table.
 - Add a 'defaults' for the operation table and remove any default
   values.

This is just code motion and there is no functional change.
sysprep: Add "notes" field for notes on shortcomings, bugs, etc.

Instead of keeping this information as comments in the source, put it
into the virt-sysprep(1) man page.
Version 1.23.13.