Use AttributeNullException instead of an InvalidOperationException.
Add targetField to schema for RenderBlock ScriptTag.
Merge pull request #175 from devatwork/renderblock-scripttag

Renderblock ScriptTag fixes.
Fixed bootstrap default menu including responsiveness on mobile devices.
Fixed thumbnail layout on the main back-office page.
Moved header down by 5 pixels.
Removed obsolete classes from navigation wells.
Modified the left back-office navigation to nav nav-pill instead of well nav.
Merge pull request #176 from Weyland/feature/bootstrap-nav

Fixed several legacy bootstrap issues
Merge pull request #177 from Weyland/feature/bootstrap-menu

Fixed bootstrap default menu including responsiveness on mobile devices.