form-choice__label should not align vertical in center in case of multiple lines

[martinbroos]

The reason we use align center is that it looks good when the font is bigger or smaller than the checkbox. But when the checkbox/radio button has multiple lines it doesn't look so appealing.

I think we should make it the default that the checkbox/radio input is aligned to the top.

[remco-freshheads]

Sure, submit a pr ;-)