Breakpoints not working after adding sourcemaps in 0.8.x

Created by: gaearon

Per @markerikson they don't always work.

We need reproducing cases to get to the root of the issue. If you can show code in which breakpoints are broken this would help.

If we don't fix them I intend to revert the sourcemaps change. We can't break breakpoints. But I hope we'll solve this instead.