Bower packages must be unversioned

[unscriptable]

bower is making the version property optional in bower.json. While this is inconsistent with npm / package.json, it's not a road block since we can simply stop versioning bower packages. If bower someday decides to allow multiple versions of a package, we can revisit the solution. For now, this should work fine.

We will need to apply a fix in [at least] two places:

1. where rave crawls for bower packages
2. where rave normalizes module names

[KidkArolis]

What about defaulting the version to "0.0.0" in the crawler, that way there is no need to change the normalization?

[unscriptable]

I noticed that you defaulted to "0.0.0" in one of the PRs. I like that this keeps the logic the same. 👍

I was briefly worried about situations wherein a package is a dependency in both npm and bower (e.g. this could happen with a popular package like when.js), but I think this still works out. Closing in favor of your suggestion. Add it to #40?