support generate separated source map file?

[txchen]

Now sourceMap is generated in the same output.css, base64 encoded.
Would be better if myth support generating the map file in another file. For example:

//# sourceMappingURL=main.css.map

In that case, output.css would be smaller, and map will only be downloaded when debugger is open.

[ianstormtaylor]

Looks like Rework supports returning an object, which could be used to created a Rework/Myth plugin that exports the sourcemap to a file instead of inlining it.

[kevva]

@ianstormtaylor, the generated sourcemap object is missing the file property and the files in sources are incorrect as far as I can see.