Review the new urchin changes.

[tlevine]

I have made some changes to Urchin, the test runner that nvm uses.
I have not yet merged these changes to urchin's master branch.
I have two suggestions regarding nvm.

I don't think the new changes broke any old features, but to make
sure they don't break any continuous integration system, you can
do either of the following.

• Use the present version of Urchin, tagged "v0.0.5", rather than using the head of the master branch.
• Try running the nvm tests with the new version of Urchin, and tell me if anything is broken.

Second, I added TAP format output, so you might consider using that.

The changes are available here

git@github.com:tlevine/urchin.git

in the branch "tlevine-2016-02". Below I have copied the relevant
section of the "HISTORY" file.

• Produce TAP output with the -t flag.
• Add a + sign in front of directories in the normal output so that they
  line up with non-directories.
• Display skipped tests in the normal output and in the TAP output.
• Correct some things in the documentation.
• Rearrange things in the documentation to be more clear.
• Pass the -e flag to exit urchin if any single test fails.
• Remove the undocumented, experimental -x flag now that shall exists.
• Display version number with the -v flag.
• Document why Urchin is called "Urchin"

These changes are made somewhat separately in the branches "exit-on-fail",
"remove-urchin-x", "tap", and "update-readme". They are rebased into one
branch, "tlevine-2016-02", for merging into "master".

[ljharb]

Ideally this would be tested by making a branch and running that in travis.

[tlevine]

I noticed in the package.json file that nvm uses version "^0.0.5" of urchin from npm, and not the master branch of the git repository on GitHub, for example. Thus, it will use version 0.0.6 when that is available, and it will not use version 0.1.0, so it is already configured to avoid using urchin versions with breaking changes. That's good.

Beyond that, this was more of a test of urchin than of nvm. I ran the nvm tests on version 731c2f3 in bash, dash, and zsh with both new and old versions of Urchin.

• bash had two failed tests that had nothing to do with the changes in urchin. I have submitted a patch for these.
• dash had loads of failed tests
• zsh had trouble with iojs versions in for both urchin versions. More tests passed with the new urchin version

zsh was the only shell where I saw different output between the urchin versions.

Considering that the new urchin version seems not to have broken anything, that it wasn't supposed to break anything, and that the package.json is configured properly, I think this issue is done.

[ljharb]

@tlevine Thanks!