Enable source maps by default to simplify configuration

[auchenberg]

Given the popularity of sourcemaps we should flip our default setting, so sourcemap support are enabled by default.

Rational:
If a source map is present it's most likely needed to resolve paths correctly. Some people don't notice the sourcemap config, and end up with a bad first time experience.

We should therefore flip the setting, and explicitly allow people to disable source maps if needed.

This would simplify the default configs too.

[roblourens]

Thoughts on this @weinand? It shouldn't break anyone since you can turn on 'sourceMaps' then debug your code without sourcemaps just fine.

[weinand]

If this change affects node2, then we will have to flip the defaults in node1 as well.
I will investigate what consequences this has in the January milestone.

[roblourens]

Right, it should be consistent across. We can change it in chrome-debug to experiment.

[auchenberg]

Let's ship this in the Chrome debugger, and evaluate the results.

[roblourens]

Enabled for chrome-debug in 2.4.2!

[auchenberg]

Yay. Let's see how people are gonna react to this.