support threads in test routines
support todo tests
only support END blocks created by parser
tests for running with threads
doc cleanup
fix pod link formatting
require threads 1.07 to fix segfaults
test cleanups
remove useless import
only load B when needed
When tied var is destroyed, set var to last value

This is most likely to happen in global destruction, when it won't be
changing anymore, so a constant variable is fine.  This lets the
DESTRUCT value live past when out tied object is destroyed.  This only
effects earlier threads enabled versions of perl.
CLONE is a class method, not an object method
update changelog
version 0.002000