COMP: Prevent confusion removing unused "weave" external project

It was initially been introduced in r14346

The files have also been added to the Slicer attic for future reference.
See https://github.com/Slicer/Attic

git-svn-id: http://svn.slicer.org/Slicer4/trunk@21962 3bd1e089-480b-0410-8dfb-8563597acbee