Fix so that when the user doesn't have permission on an annotation and the annotator instance is readOnly it will not try to hide the undefined controls
Merge pull request #162 from deds/master

fix so that users without update/delete permissions on readOnly annotator doesn't try to operate on non-existent controls
get the lowest common ancestor instead of highest

Fix #166 as reported by @jujug42
Merge branch 'master' of github.com:okfn/annotator into develop