Add ENWC from bzr://bzr.savannah.nongnu.org/enwc/trunk

git-subtree-dir: packages/enwc
git-subtree-mainline: 8973bd8b49ff3f383645921dfaa7ce71abc9a91f
git-subtree-split: 853350e2594af2ff5d86042612f8c8c3e5214300
Fix up copyright names in ENWC; tweak packages/README.
* packages/enwc/enwc-pkg.el: Add missing file.
Sync with enwc/master