Make sure the original line location is shown

# Before
![Before](https://f.cloud.github.com/assets/485535/187417/cc45cc20-7d59-11e2-9adb-fbbadb07b9c7.png)
Currently always when a binding error occurs, then in the console the error occurs at line 1936 (or so) in knockout-2.2.1.debug.js
That sucks.
The original line location is masked out and being lost.

# After
With this change we're displaying the same kockout-wish error message but preserve the original line location!
![After](https://f.cloud.github.com/assets/485535/187418/d4812ee8-7d59-11e2-8381-36c5612f199a.png)

This is very handful, please merge the pull request.