Remove support for old browsers

[romamatusevich]

Maybe we can remove support for:

Chrome, Firefox < current version
Android < 2.3
Safari < 5
iOS < 5
Opera < 15

Any opinions?

[drublic]

I think most stuff is up to date in the repo. Any concrete stuff you would like to see remove?
There is no real "browser support" yet though. We could add this.

[romamatusevich]

x-linear-gradient, x-multiple-backgrounds, x-multiple-colored-gradient:
remove -o-, -moz-

x-transform, x-transition, x-tab-size:
remove -o-

[drublic]

Thanks so much. I've updated the the mixins with your suggestions.

[romamatusevich]

For x-multiple-backgrounds we could also remove Sass variables:
$combined-background-moz: ();
$combined-background-o: ();

For x-tab-size also remove from mixin: -o-tab-size: $value;.

Thank you for the abandonment of old browsers.

[drublic]

Thanks for the heads up!
I've made the changes as required. We should be up to date now.

[romamatusevich]

Thank you for changes.