Fog Control Command

Adds the /fog command that allows you to control the fog.

/fog <target> set <color|start|end> <value>   - set the selected value

/fog <target> add <start|end> <value>   - adds the selected value to the default value

/fog <target> default <color|start|end>   - sets the value to default

When changing color, the <value> is <red> <green> <blue>