rename to suggest the read order.

--HG--
rename : examples/probe.py => examples/00_probe.py
rename : examples/extract.py => examples/01_extract.py
rename : examples/extract_iter.py => examples/02_extract_iter.py
potential crasher bug: do not free data on exception in FrameBinder.
unit tests and related fix. Raise the coverage again.
more tests and more mocks.
Pull from HG.