Let setPosition set stick to EOL flag.
Let LineEndMotion set stick to EOL flag.
LineStartMotion allways resets stick to EOL flag.
Let '+' and '-' reset stick to EOL flag.
Unbind and del StickToEOLCommand / LineStartCommand

These commands are made obsolete by the changes in setPosition(). The
motions themselves will state whether the EOL flag should be reset,
hence working in any CommandBasedMode.
Remove unused 'stickToEOL' / 'stickToBOL' methods.

All of this is now handled by setPosition.