CTC/Makerbot/Flashforge extruder - flexible filament upgrade

Redesigned extruder block with smaller drive gear hole (11.8 instead of 13 mm) -> longer filament support between the drive gear and hot end so flexible filament does not get stuck in between.

As CTC that I own is an Makerbot Replicator 1 (dual) clone, it should also work for Makerbot Replicator 1 and FlashForge printers.

Update 01.04.2015: Changed hole diameter to 11.8 so it does not need sanding, moved filament hole a bit, made a bigger diameter hole on the bottom so it does not touc