--version

Potentially controversial implementation but `--version` is a pretty widely supported command.

```
mandrews@MATT ~/sandboxes/origami-build-tools (version) $ git --version
git version 1.9.1
mandrews@MATT ~/sandboxes/origami-build-tools (version) $ npm --version
1.4.10
mandrews@MATT ~/sandboxes/origami-build-tools (version) $ gulp --version
[14:04:04] CLI version 3.8.8
[14:04:04] Local version 3.8.8
mandrews@MATT ~/sandboxes/origami-build-tools (version) $ nodenv --version
nodenv 0.3.3
mandrews@MATT ~/sandboxes/next-engels (master) $ jshint --version
jshint v2.5.6
mandrews@MATT ~/sandboxes/next-engels (master) $ node-inspector --version
v0.7.4
mandrews@MATT ~/sandboxes/next-engels (master) $ browserify --version
5.11.1
mandrews@MATT ~/sandboxes/origami-build-tools (version) $ grunt --version
grunt-cli v0.1.13
mandrews@MATT ~/sandboxes/origami-build-tools (version) $ mrt --version
Meteorite version 0.7.4
Release 0.8.2
mandrews@MATT ~/sandboxes/origami-build-tools (version) $ static --version
node-static 0.7.3
```

Seems to be some variety in the format it returns but most nodey things seem to just return some version semver (browserify, npm, node, node-inspector, nodemon) so that's what I did for OBT.