Fix: Can't set scissor with negative width and/or height.

[blogdron]

Small fix for

Error: luigi/widget/text.lua:414: Can't set scissor with negative width and/or height.
stack traceback:
	[love "boot.lua"]:352: in function <[love "boot.lua"]:348>
	[C]: in function 'intersectScissor'
	luigi/widget/text.lua:414: in function 'func'
	luigi/hooker.lua:79: in function 'callbacks'
	luigi/event.lua:16: in function 'emit'
	luigi/painter.lua:234: in function 'paint'
	luigi/painter.lua:204: in function 'paintChildren'
	luigi/painter.lua:229: in function 'defaultAction'
	luigi/event.lua:18: in function 'emit'
	...
	luigi/painter.lua:204: in function 'paintChildren'
	luigi/painter.lua:229: in function 'defaultAction'
	luigi/event.lua:18: in function 'emit'
	luigi/painter.lua:215: in function 'paint'
	luigi/input.lua:19: in function 'handleDisplay'
	luigi/backend/love.lua:138: in function 'func'
	luigi/hooker.lua:79: in function 'draw'
	[love "callbacks.lua"]:168: in function <[love "callbacks.lua"]:144>
	[C]: in function 'xpcall'

Sometime width coord is negative.
Im just lock minimal size/pose to zero.