fix(session): resolve identity only if we have valid token

SD-1085
Merge pull request #549 from petrjasek/devel

fix(session): resolve identity only if we have valid token
feat(metadata): Enable metadata editing in article edit screen
fix(archive): display abstract in preview pane
fix(authoring): Minor authoring UI fixies
fix(metadata): fix spacing
fix(authoring): unlock item when it was locked

when there were no changes to item there was no unlocking

SD-1084
[SD-1067] Initial urgency wire up
Merge branch 'devel' of https://github.com/superdesk/superdesk-client into feat-search