Allow css variable in style binding (object syntax)

I am not sure if this is intentional, I would like to be able to do:

<div :style="{ '--color': player.color }">…</div>

instead of:

<div :style="'--color :' + player.color">…</div>

I was able to find the workaround quickly thanks to the doc search here: http://vuejs.org/guide/migration.html#v-bind-style-with-Object-Syntax-and-important-deprecated

It’s a bit different from !important so I would like to push for this feature.

Thanks a lot for your good work, I can work on a PR if you agree with this proposition.

[phanan]

@defcc --color is a CSS3 variable syntax.

[yyx990803]

Fixed in 4b8eb75