hasRole rename - update readme

`hasRole` was renamed from `isInRole` as part of https://github.com/OptimalBits/node_acl/commit/e40c326a13f3a6fc81ff606bed68a585235bced3, but the README was not updated accordingly.
Merge pull request #67 from fyockm/patch-1

hasRole rename - update readme
Fix addRoleParents param descriptions