PlayerRob

- Added check for config values going negative if they were set to zero

- Added blindness potion effect to player while he is being robbed

- Added auto-update option. Disabled by default in config

- Added command to update the plugin /robupdate. Disabled if autoupdate is disabled in config

- Added permission for /robupdate 'rob.update'

- Removed ability of robbed players to break and place blocks while being robbed