Mendel90 Wades block with added J-Head lip

I was occasionally getting jams where the J-Head hotend meets the Wades block. Partly due to me widening the filament wide opening there by accident. Either way I noticed that my J-Head hotend had some empty space right at the top by the filament path. I wanted to block this to minimize the risk of buckling/bending/jams.

I used the Wades block from Nopheads github repository and added a small "lip" to handle the described issue.

Since I've added this I haven't gotten any jamming the last f