All 4 of these test files should be executable.
Fixing these test files that have never been run
`&>` is a bash-specific extension for redirecting both stdout and stderr.
copy-packages: ensure that `nvm_version` is also applied to compare the provided version to the current one.
install: Ensure that if a version is not provided, we don't try to shift a nonexistent argument.
install: don't output "additional options" when there are none.
Merge pull request #523 from creationix/run_slow_nvmrc_tests_too

Actually run all tests; fix some bugs