Add a new mode: „console“

In „console“ mode the result is always a console.log of the statements line by line. Each line will just be evaluated and console.logged. 

# Use case
Explainer posts. 
## Projection creation
``` 
var projection = d3.geoAlbers();
projection([4,5])
```
Instead of 
``` 
var projection = d3.geoAlbers();
console.log(projection([4,5]))
```