Fix org.getMembers() to 'wrap' returned users for post-populating

This fixes an issue introduced with PR #66 in commit fee02a3d16 - the
`getMembers()` method switched to using paging, but lost the code that
populated the users with a full set of values.

This commit just applies 'wrapping' to all users returned, so that methods
like `user.getCreatedAt()` can be called on returned users without throwing
a NullPointerException - the reference to 'root' allows the user objects to
populate themselves.