Source map doesn't work on a build

[ofilippov]

Steps to reproduce:

1. Create a new qooxdoo application
2. Build it with command:
   qx deploy --out=build --app-name=myapp --source-maps --save-source-in-map
3. Open build in a browser and try to use source map.

Expected result:

You can use source map to debug a build

Actual result:

Breakpoint on a source map file doesn't correspond to an actual breakpoint position in index.js file

[ofilippov]

Example of a simple application:
myapp.zip

Breakpoint in source map file:

Same breakpoint in index.js file: