ui-enhancement: board and issue listing ui change

- board: add notice label & height
- issue: distinguish author and assignee
- issue: change position of miestone tag
- issue: add label style to label
- both: place author avatar image at first of row
- both: change position of attachment icon
- both: various style change. magin, padding etc.
Merge pull request #213 from doortts/enhance/listing-ui

ui-enhancement: board and issue listing ui change