Fix for issue #81 - sourceMappingUrl is wrong.

[lewie9021]

Small change discussed in issue #81. Making the change indeed fixes source mapping so I thought I'd create this pull request.

[jorrit]

Maybe you can add a comment to the line to explain why it is necessary, for future reference.

[jhnns]

I see, we need to omit the source maps because otherwise webpack's source map comment would be ignored. Without .omitSourceMapUrl it looks like this:

body {
  background: lightgrey; }

/*# sourceMappingURL=test/output/sass.map */  <-- from node-sass
/*# sourceMappingURL=data:application/json;base64,...*/  <-- from webpack

[jhnns]

Will be published soon. I just need to do some tests and I'll update the docs. Also related to #104.

[jhnns]

Shipped with 1.0.4