Enumeration: graph type

Types of graphs for the statistics panel.

--Possible values--
The value is one of the following options:
! Value		Dimensions	Sketch	Description
| @bar@		1		<img src="graph-type-bar.png" alt="bar graph"/>
		 	 	One bar for each value on the axis, the height represent the number of cards with that value.
| @pie@		1		<img src="graph-type-pie.png" alt="pie graph"/>
		 	 	A pie graph, the size of the slice represents the numer of cards with a particular value.
| @stack@	2		<img src="graph-type-stack.png" alt="stack graph"/>	
		 	 	One bar for each value on the first axis, bars for each value on axis2 are stacked on top of each other.
| @scatter@	2		<img src="graph-type-scatter.png" alt="scatter graph"/>
		 	 	Scatter plot, the size of the circles corresponds to the number of cards with those two values.
| @scatter pie@	3		<img src="graph-type-scatter-pie.png" alt="scatter-pie graph"/>
		 	 	Scatter plot, the size of the circles corresponds to the number of cards with those two values.
		 	 	Each circle is a small pie graph for the third axis.

--Examples--
> type: bar
