Try Gen7 for Melzi board for next printer
Gen 7 IDE might be the current thing that contains support for sanguino and newest arduino IDE
I think the name should be something like:
Gen 7 hardware support for Arduino IDE
as the current wording looks like Gen7 is another IDE for Arduino. I don't think that is the case
Try this next Installation
Have Arduino IDE already available. In case Arduino IDE is already running, quit it. Download and unpack the IDE support package. Links see above. Open the folder containing Arduino in your file manager. [ The following is Not applicable to me] --> On Mac OS X this is done by right-clicking the Arduino.app icon and choosing "Show package content". Then navigate further down to Contents/Resources/java. -- Find the folder Gen7 in the support package and move it into the hardware folder inside the Arduino package.
There are also install instructions inside the Gen7 Arduino IDE Support package.
Note: for Linux/Unix users, if you install using your package manager it may be difficult to find your arduino/hardware folder, and even after you find it you might not be able to copy into it. Just make a "hardware" folder in the "sketchbook" folder of your home directory and put the Gen7 support folder in there. The "sketchbook" folder appears when you run the IDE the first time.