allow grid captcha yIconOffset=0

lib/captcha/generators/grid.js

@@ -9,7 +9,7 @@ const gm = require('@fatchan/gm').subClass({ imageMagick: true })
 
 module.exports = async (captchaOptions) => {
 
-	const { size, trues, falses, imageSize, noise, edge } = captchaOptions.grid;
+	const { size, trues, falses, imageSize, noise, edge, iconYOffset } = captchaOptions.grid;
 	const width = imageSize+padding; //TODO: these will never be different, right?
 	const height = imageSize+padding;
 
@@ -37,7 +37,7 @@ module.exports = async (captchaOptions) => {
 
 		for(let i = 0; i < size; i++) { //for character in row
 			const index = (j*size)+i;
-			const cyOffset = await randomRange(0, captchaOptions.grid.iconYOffset);
+			const cyOffset = iconYOffset > 0 ? (await randomRange(0, iconYOffset)) : 0;
 			let character;
 			if (boolArray[index] === true) {
 				character = trues[(await randomRange(0, trues.length))];