add npm-registry-couchapp dev dep
Run the npm-registry-couchapp tests along with npm tests

This test will fail if couchdb isn't installed
bump tar and fstream deps
doc: revert accidental whitespace change
Add user-friendly errors for ENOSPC and EROFS.

Fixes #5101.
Update EROFS error to be a bit more informative.
Fix small typo in synopsis in npm-link.md.

Fix small typo (add 's') in command's synopsis in npm-link.md.
Remove concerns of package republishing from shrinkwrap docs

Republishing packages is no longer possible.
version.js: Fix indentation
Remove spurious `er.code =` assignments.

They literally do nothing in all cases.
removed duplicate function
doc: npm-explore can't handle a version

Closes #5323
Bump npm-registry-couchapp for test goodness
making it so that you can pass arguments to run-scripts.
made old tests work.
updated documentation.
added test for running script with args.