Introduce light-yellow color
Create qtip-warning
Add has-warning class
Create and use $.fn.tooltip
Fix typo
More flexible form error display

- support custom tooltip anchor
- add helper to reposition qtips (e.g. when adding items to the DOM)
- fix error border for i-table-widget
Add asterisk for required fields
Change fieldset layout
Support **kwargs in custom widgets
Make required fields more obvious
Align required asterisk for multi-line fields
Disable :invalid style
Fix margin of message boxes below page header
Rename .admin-page-* to .content-page-*

Also moved it from admin.scss to main.scss
It's not only useful for admin pages but also e.g. in some event
management areas.
Include admin.scss on all admin pages