Adaptative RED select in chisel mode

Adapt the Red selection for the mode of the chisel tool.
To see what we will delete.

![2014-12-04_21 16 25](https://cloud.githubusercontent.com/assets/401965/5305534/c35d90e0-7bfc-11e4-984f-754a07effc92.png)
![2014-12-04_20 29 01](https://cloud.githubusercontent.com/assets/401965/5305199/be6ee97e-7bf9-11e4-94b0-1bc9159f8246.png)
![2014-12-04_20 29 32](https://cloud.githubusercontent.com/assets/401965/5305200/be798226-7bf9-11e4-919d-614a4aabd9ae.png)
![2014-12-04_20 29 45](https://cloud.githubusercontent.com/assets/401965/5305201/beaf0680-7bf9-11e4-8fab-a28da0d62d70.png)