Inline source maps being request with path

[auchenberg]

This change 2004283#diff-a14450dbe613721f5b4d8361cc0e5ec0R244 has broken the inline source map support, as it causes the inline-source map to be fetched from the network with the base url prefixed.

Actual:
sourceMappingURL: "http://localhost:7000/sourcemapsexample/build/data:application/json;base64,eyJ2Z

Expected:
sourceMappingURL : "data:application/json;base64,e"

[auchenberg]

Change could be:

          var sourceMappingURL = _findSourceMappingURL(source)
          var isDataUrl = sourceMappingURL.substr(0, 5) === 'data:'

          if (sourceMappingURL[0] !== '/' && !isDataUrl) {
            sourceMappingURL = fileName.substring(0, fileName.lastIndexOf('/') + 1) + sourceMappingURL
          }

[eriwen]

Fixed by #18