Adds:
- Clickable commands in /myvillager
- title message when entering selection mode
- some sounds of command and join and exit selection mode

Fixes:
- the problem that tab completer is not completed.
- missing message in zh_CN and zh_TW language files.

Changes:
- package rename
- in game commands (/mv villager and /mv player are combined into /mv group)
- The type of selection mode is optional now. If there is no argument "multiple" in command, single selection mode will be selected.

It is recommended to delete the language file and wait for its re-generating.