Fix bearing names
typo in doc/dimensions.md
Use fillet function for idler, zero base_extra_depth
Fishbone gears for wade extruder (wide, 13:37 ratio)
Added some howto on contributing
Revert "Fix bearing names"

This reverts commit 2c8bf4c0c580ab066c3130b77fcf7b1293cbaff6.
Refactor plate screw, fix Z for single plate
Merge pull request #46 from AxTheB/master

Z axis for single plate, wade extruder is now complete.