Bug fixes and API improvements

Changed

• Adjust toolbar positioning on component change

Added

• Added onActive method in ComponentView which executes on active event
• Added the possibility to open the modal with title and content via options
  eg. editor.Modal.open({ title: 'Title', content: 'Content' })
• Added the possibility to append label on component toolbar buttons
• Added run and stop methods in Commands module

Fixed

• Ensure the trait gets the initial value. Fixes #1290
• Avoid canvas focus check in ComponentDelete command. Fixes #1298
• Fix the open-assets call in Style Manager input (file type). Closes #1241