Fixes vertical-three-colors in Firefox

[Marmelatze]

The less mixin for vertical-three-colors doesn't seem to work in Firefox 13.0.1.
It just displays the default background-image option. It looks like Firefox want a percentage value.

I hope *100% works fine.

Old Request was #4055

[travisbot]

This pull request passes (merged fa38ab5 into 88deb08).

[mdo]

I hope *100% works fine.

Well, did you test it :)?

[Marmelatze]

Of course i tried it with #gradient > .vertical-three-colors(#cc0303, #920000, .26, #410000);.
It works well in Chrome, but fails in Firefox and just displays the simple background.

[Marmelatze]

How did you call the mixin?

[jcdirks]

This patch makes the mixin break in Firefox if it's called with px like
#gradient > .vertical-three-colors(#ffffff, #eeeeee, 50px, #eeeeee);
I'd rather suggest to use 26% instead of .26 for procentual values and revert this patch.

[skoepp]

Maybe you should change the default value @colorStop: 50% to @colorStop: .50 to clearify the usage of the mixin.

From my personal perspective I would prefer to use the mixin in this way:
#gradient > .vertical-three-colors(#DBDBDB, #F9F9F9, 75%, #DDDDDD);

[jcdirks]

Let's just throw in the colorStop value directly and not asume or dictate the use of a procentual value. Using px is allowed and makes sense to e.g. fake shadows or align with logo images.

[thomaspark]

As others have stated, this patch breaks mixin when percentage or pixel value is passed. Should be reverted I think.