Supporting versioned install

[wosinekm]

Current repository doesn't support installing exact version:

$ npm install -g phantomjs@1.9.2

fails with

Error: version not found: 1.9.2 : phantomjs/1.9.2

According to npm install @ we need tags related to each version.

[monbro]

So you are actually able to do versioning. The only thing I experience is that the version numbers are kind of different to the original once: 1.9.2-0 https://github.com/Obvious/phantomjs#versioning

[nicks]

Use npm view phantomjs to see all available versions.