Adds:
- extra features of company area:
> "Area" in company menu
> Area's "create", "list", "sell", "rent", "market" in menu
> Area sell and rent function, which allows you to push the area to area trade market for sale/rent.
- area protection (can be disabled in config.yml)
- position permission: "AREA_MARKET_RENT", "AREA_MARKET_SELL", "AREA_RENT" and "AREA_BUY"
- area's entering/quitting actionbar message.
- players on a broke company will receive special message during the salary payment time.

Changes:
- Default BuildingArea will select built-in CompanyArea for replacement.

Fixes:
- Player can still create area if there are existed areas in the selection.
- incomplete TabCompleter