login url directs to admin login
modified field
moving to a separated private method the lookup for candidate text-segments of a Relation
Fixed EvidenceForm so only reports has_changed when actually did (so modification date is not corrupted)
requiring login for using label-evidence view
if user labeled, storing its name on the labeledevidence
created logic, url and view for navigating labeled segments
remove js-navigation
adding links for navigation, and info about current existent labels
some basic styles
fixing logic of get_next_to_label, and tested that and navigation
Merge branch '235-warning-if-was-already-labeled' into relational-storage