make the padding parameter order the same as in the Android Framework

[martinbonnin]

see discussion in #535

[elihart]

I'm not sure why I ordered it the way I did, but I see your point about changing it.

I'm hesitant though because it won't be a compiler breaking change, it will just have different runtime behavior, so it would be really easy for people to forget to update.

[elihart]

I think we can include this with 3.0 - but I would also like to change the main Padding constructor for pixels to be Padding.px(...) to match the new dp and resource support. this will make it more likely that people update correctly too I think

[martinbonnin]

Padding.px pushed. If we really wanted to make sure everyone updates their code, we could rename all these static methods:

• Padding.fromPx(), Padding.fromDp()
• or Padding.createPx(), Padding.createDp()

[elihart]

Thanks! I don't think we need to rename those too, they are fairly new and probably not used as widely.

I'll wait to merge this until we are ready for 3.0, and I'll make sure I headline the changelog with this breaking update.

Appreciate the contribution!