Rename woof to wurf

Summary:
Now the important pull requests have been submitted, it's ready to
be renamed to wurf.

Configuration files are documented to be wurfrc, but woofrc is still
read to maintain compatibility.

Ref T2058

Test Plan:

• man ./doc/wurf.1
• wurf -U
• Check how the different configuration files are parsed

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T2058

Differential Revision: https://devcentral.nasqueron.org/D3538