* [top toolbar] fixed the position of the vertical line between 2 sides
- fixed it for all the pages
- removed the duplicated 'div.main-panel' in 'lib-content-view'
* [search] modified the UI
* [top toolbar] redesigned the notification
* [top toolbar] avatar & the triangle: modified the UI
* [left side panel] updated the UI; fixup & improvement
* [misc] modified links' color, op-icon, and etc.
* [misc] updated UI for share dialog, other dialogs, & 'more operations' dropdown
* [misc] UI: modified markdown side panels, comment panels, input/textarea placeholder
* ['user settings' page] modified UI
* [shared dir upload link page] modified the UI
* [user settings] modified the UI
* [user settings] fixup
* [seafile-ui.css] use an updated one (modified color of buttons)
