Change jquery dependency to '*'

Component does not support range dependencies as far as I can tell per
the spec on the Wiki. Without this change,

   $ component install -v components/bootstrap

fails with the error message

   error : failed to fetch https://raw.github.com/components/jquery/>=1.9.0/component.json, got 404 "Not Found"

Fixes #20
Merge pull request #21 from BardurArantsson/fix-jquery-dep

Change jquery dependency to '*'