Usually this library will append media queries in separate <style> elements.
However, doing this changes the cascade such that a media rule will be used over
a non-media rule. This is because the media rule is removed from its position
and appended after everything else. It is a common case that a non-media rule
will override a media rule, so this inversion of the cascade makes it very
difficult to style for all browsers using this polyfill.

Turn on this option by setting `window.RESPOND_REPLACE_STYLES = true` before
sourcing this script. It will remove every stylesheet it finds and move all CSS
into the `media="all"` stylesheet that is appended, minus the inactive media
query rules and those of other media types, like print. The other types are
appended in the usual manner.

Bug was introduced when DRYing code to the `insertCss` function.

As a result of rebasing the `RESPOND_REPLACE_STYLES` option code onto
1c8ce14 (after previously being on 1.4.2), the
replace index was being calculated as -1, meaning the query could not be found
in the total styles. This was because comments are now being stripped.

To fix that, the stripping of comments and keyframes from styles are done
immediately in the `translate` function, and then stored with their replaced
urls if `RESPOND_REPLACE_STYLES === true`.

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