That's the problem with having two eyes and ten fingers...
I tend to use them in that proportion!
Just brought down the latest code from the master and trying it.
Using ABSPrusa Mendel Zaphod with Pronterface and slic3r 1.3.0. Printing well with 3mm PLA and ABS through 2 x J Head Mk IV b and Wade Geared Exruders. Controlled using RAMPS1.4 board running Marlin_v1.1.9