[oe] naming tasks

[David Farning]

Still working on the manual!

I've come across a question on how tasks are named.  What is the
purpose of the prefix patch in the def patch_do_patch found in
the patch class?  Most task seems to be called do_taskname.
I am thinking that it has something to do with
scope but I am unsure.

addtask refers to do_patch and
EXPORT_FUNCTIONS refers to do_patch

Thanks
David