Merge pull request #309 from wolfmanjm/upstreamedge

M500 save current settings for E only if different from the config value
Merge pull request #310 from wolfmanjm/upstreamedge

Set previous_nominal_speed to 0 if the next block is a zero move block s...
Merge pull request #311 from wolfmanjm/upstreamedge

Make minimum planner speed configurable
Changed SerialConsole definition for MRI/Debug UART so it supports all 4 locations
Merge pull request #313 from powertomato/feature/mri_all_locations

Changed SerialConsole definition for MRI/Debug UART so it supports all 4...
provide one method to add gcode to blocks, reduce code duplication
add HeapRing: a new RingBuffer constructed from the trials and tribulations of the existing one
Change Conveyor,Planner,Block to use HeapRing
HeapRing: missed a free() in a corner case
Revert "Change Conveyor,Planner,Block to use HeapRing"

This reverts commit 5bd37b4d1309789eb1dc8f3300f0ee206901a171.
Adjst corexy homing speed for diagonal moves to match X or Y moves
Merge remote-tracking branch 'upstream/edge' into upstreamedge