feat(task): task preview fix
feat(notification): add link to item

SD-722 SD-656
fix(mentions): remove unused file
Merge remote-tracking branch 'petr/devel' into devel
chore(bower): update angular to rc2
fix(notification): add style to links
Merge remote-tracking branch 'nikola/devel' into devel
fix(users): make validators work with angular 1.3

the way validators are working is changed since 1.3rc1
fix(mentions): sort users in list

and limit them to 5

SD-656 SD-743