Data type: symbol variation

--Overview--

A variation of a symbol, describes color and border.

--Properties--
! Property		Type			Default		Description
| @name@		[[type:string]]		''Required''	Name of this variation, refered to by the [[fun:symbol_variation]] function.
| @border radius@	[[type:double]]		@0.05@		Border radius of the symbol.
| @fill type@		@solid@ or @linear gradient@ or @radial gradient@
			 			@"solid"@	How to fill the symbol.

Depending on the @fill type@ there are additional properties:
! Fill type		Property		Type		Description
| @"solid"@		@fill color@		[[type:color]]	Color to use for filling the symbol.
| ^^^			@border color@		[[type:color]]	Color to use for the border of the symbol.
| @"linear gradient"@	@fill color 1@		[[type:color]]	Color to use for filling the symbol at the center of the gradient.
| ^^^			@border color 1@	[[type:color]]	Color to use for the border of the symbol at the center of the gradient.
| ^^^			@fill color 2@		[[type:color]]	Color to use for filling the symbol at the ends of the gradient.
| ^^^			@border color 2@	[[type:color]]	Color to use for the border of the symbol at the ends of the gradient.
| ^^^			@center x@, @center y@	[[type:double]]	Position of the center point of the gradient (in the range 0 to 1)
| ^^^			@end x@, @end y@	[[type:double]]	Position of the end point of the gradient (in the range 0 to 1)
| @"radial gradient"@	@fill color 1@		[[type:color]]	Color to use for filling the symbol at the center of the symbol.
| ^^^			@border color 1@	[[type:color]]	Color to use for the border of the symbol at the center of the symbol.
| ^^^			@fill color 2@		[[type:color]]	Color to use for filling the symbol at the edges of the symbol.
| ^^^			@border color 2@	[[type:color]]	Color to use for the border of the symbol at the edges of the symbol.

--Examples--
'Common' and 'uncommon' magic expansion symbol styles:
>variation:
>	name: common
>	border radius: 0.10
>	# White border, black fill
>	fill type: solid
>	fill color:   rgb(0,0,0)
>	border color: rgb(255,255,255)
>variation:
>	name: uncommon
>	border radius: 0.05
>	fill type: linear gradient
>	# Black border, silver gradient fill
>	fill color 1:   rgb(224,224,224)
>	fill color 2:   rgb(84, 84, 84)
>	border color 1: rgb(0,  0,  0)
>	border color 2: rgb(0,  0,  0)
