Kossel 2040 corners

I removed the front three alignment tabs from the vertical channels because I couldn't get T-nuts into the channel with them in place.

I also notched the horizontal alignment tabs for t-nuts because when I tightened down the screws there was still a bit of wobble on the horizontals where the t-nuts bottomed on the out on the tabs and didn't make contact with the aluminum extrusion.

Parts printed perfectly!

[Hatchbox Orange PLA](https://www.amazon.com/HATCHBOX-3D-Filament-Dimensional-Accuracy/dp/B00J0EE1D4/ref=as_li_ss_tl?_encoding=UTF8&pd_rd_i=B00J0EE1D4&pd_rd_r=DJ0WTWQE1H44JN1F1J1D&pd_rd_w=IzzVd&pd_rd_wg=0mVAW&pf_rd_p=396d1c33-ff6b-4ac3-89ee-4ce25c5633d6&pf_rd_r=DJ0WTWQE1H44JN1F1J1D&psc=1&refRID=1EBY1699EZFB81A5DY90&linkCode=sl1&tag=elitetrackllc-20&linkId=854ac3c19b90cf23e88ade2a22beb0d2&language=en_US) - All corners
[Hatchbox White PLA](https://www.amazon.com/HATCHBOX-3D-Filament-Dimensional-Accuracy/dp/B00J0EE1D4/ref=as_li_ss_tl?_encoding=UTF8&pd_rd_i=B00J0EE1D4&pd_rd_r=D