Updated Hopper for Ditting 807LS with bellow

This is an updated version of a hopper with bellow. 

The initial model works fine, however when switching from pour over to espresso a bellow will be helpful to clear the left over fines.

The hopper bellow and base are based on my Ceado bellow hopper remix. 

v2: I added a shield into the hopper base to prevent popcorning.

v3: Replaced the shield with a slider, to choose when beans go in. Added additional walls to keep beans better inside.