set the xPad and yPad to zero as default value

[zixun]

I have an idea: set the xPad and yPad to zero as default value.so that we can have an api that needn't pass the xPad and yPad if xPad is 0 and yPad is 0 . because almost every API in Neon contains parameters of xPad and yPad,and almost every time I pass zero to them.If the default value is Zero,I will needn't pass zero any more. My code will be nicer~

[mamaral]

Wouldn't Xcode then autocomplete a bunch of different versions of the same method, making quick implementation a bit annoying?