Relative url()s to files within src/ do not work

[phillipskevin]

If you create a url() from an image that is within your project's src/ folder like:

background-image: url("./assets/1-banner.jpg");

in DoneJS 0.9, the CSS that is injected into the SSR'd page would have:

background-image: url(/src/assets/1-banner.jpg);

in DoneJS 1.0, the SSR'd page has

background-image: url("assets/1-banner.jpg");

which is not correct.

[phillipskevin]

In done-css 2, this was handled here: https://github.com/donejs/css/blob/v2.0.3/css.js#L107-L109.

[phillipskevin]

done-css is using steal-css now and this code is skipped during SSR: https://github.com/stealjs/steal-css/blob/master/css.js#L157-L163.

[phillipskevin]

This is fixed in steal-css@1.2.2.