Use an unminified PlayCanvas engine script in editor

[leonidaspir]

Now that the editor API has become official, and more and more developers give editor scripting a try, it's a common scenario to get a PlayCanvas engine related exception.

Right now the engine script that is running in the editor is minified, making it hard to debug that kind of exceptions.

[yaustar]

In the meantime, there is an undocumented method to run the Editor with a specific version of the engine which is to use use_local_engine in the same way as you do with the launch tab

[leonidaspir]

Nice, that works fine in the meantime, thanks @yaustar.

[yaustar]

Also, kungfooman recently added sourcemaps to the engine build which should help further :)