Added gotcha remarks on default yeoman webapp generator producing sas…

…s debug blocks breaking respond.js.

This hopefully helps out developers who have sass debug blocks enabled out of the box without explicitly enabling them (so that they might not recognize this caveat line when they first see it). The related discussion was in scottjehl#148.

README.md

@@ -85,7 +85,7 @@ respond with a 200 status.
 
 - If you have more than 32 stylesheets referenced, IE will throw an error, `Invalid procedure call or argument`. Concatenate your CSS and the issue should go away.
 
-- Sass/SCSS source maps are not supported; `@media -sass-debug-info` will break respond.js. Noted in issue [#148](https://github.com/scottjehl/Respond/issues/148)
+- Sass/SCSS source maps are not supported; `@media -sass-debug-info` will break respond.js. Noted in issue [#148](https://github.com/scottjehl/Respond/issues/148). Source maps may be enabled by default in apps produced by the [Yeoman webapp generator](https://github.com/yeoman/generator-webapp) but can be disabled by removing the `debugInfo` override in the Gruntfile.
 
 - Internet Explorer 9 supports css3 media queries, but not within frames when the CSS containing the media query is in an external file (this appears to be a bug in IE9 — see http://stackoverflow.com/questions/10316247/media-queries-fail-inside-ie9-iframe). See this commit for a fix if you're having this problem. https://github.com/NewSignature/Respond/commit/1c86c66075f0a2099451eb426702fc3540d2e603