code: function searchDependencies (dependencies, root) {
    if (!dependencies) {
      return Promise.resolve([])
    } else {
      var pluginPkgPath
      var pluginPkgPaths = []
      for (var key in dependencies) {
        pluginPkgPath = path.join(root, 'node_modules', key)
        pluginPkgPaths.push(pluginPkgPath)
      }
      return Promise.all(pluginPkgPaths.map(function (pkgRoot) {
        var pkgPath = path.join(pkgRoot, 'package.json')
        return readJSON(pkgPath)
          .then(function (pkg) {
            if (pkg.vigour && pkg.vigour.plugin) {
              return searchDependencies(pkg.dependencies, pkgRoot)
                .then(function (deps) {
                  return searchDependencies(pkg.dependencies, root)
                    .then(function (otherDeps) {
                      return deps.concat(otherDeps)
                    })
                })
            } else {
              return false
            }
          })
          .catch(function (reason) {
            return false
          })
      }))
      .then(function (arr) {
        arr = _flatten(arr)
        return pluginPkgPaths.concat(arr.reduce(function (prev, curr) {
          if (curr) {
            prev.push(curr)
          }
          return prev
        }, []))
      })
    }
  }
docs: /* searchDependencies
  gather info on dependencies and nested dependencies, search for
  package.vigour.plugin info