UI 1.7: Minor bugs (deleteAll, cookie changed not updated...)

[Yvon TANGUY]

Lots of minor bugs:
- DeleteAll: If there was protected cookies after delete all, the textbox search filter was disabled.
- DeleteAll: Focus the tree if there is protected cookies in the view.
- Textbox search filter: may not be disabled/enabled when appropriate.
- Click on "(Un)Protect cookie": focus the tree after the action.
- Show the cookie editor: focus the tree after the action.
- Show the preferences: focus the tree after the action.
- Key events: The delete key do not delete the selection.
- Prevent display the context menu if no cookie selected.
- Event cookie changed: The view was not updated if the cookie is selected.
- Event cookie changed: Some cookies properties was not updated.
- Save/Restore state: Add the current selected item, not only the open state.
- Import/Export: Save the state before import.
- When a cookie change, sometimes the wrong cookie is updated in the view.