Optimization in background Bookmark.search
Use KeyEvent.stopPropagation

Instead of returning false from event handlers
Do not cycle non-stop until page is loaded
Do not search bookmarks/history if 'completion_items' doesn't include them
Remove unused extension methods for String
defaultSearchUrl should search in Google if no default
Do not try defaultSearchUrl when opening from clipboard

As it will already be called by fixUrl
Fix editing via external editor
Minor refactoring of externalEditor
Use isValidURL pervasively
Optimize getKey and Dialog.handleInput
Allow continuing search after been canceled
Refactoring