add plan buffer remaining for 'P' and block buffer remaining 'B'

Display unknown XYZ on the LCD as "---"

Use MSG_OK in M105

Use Mendel default for INVERT_Y_DIR

Consolidate arc code, remove motion_control.*

- Also show 2 digits past decimal for Z on DOGM

Formatting tweaks

Fix heating error message

Combine thermal runaway and watch-period

Split up prepare_move by type

Feature: Add RAMPS CNC Controller Board

improve sled handling

- For better encapsulation add inlines for each prepare_move type
- Move controllerFan vars inside the function as statics
- Some formatting cleanup
- Rename `ClearToSend` as `ok_to_send`

Always do st_synchronize() before G28

add missing endstop-bits
(Travis don't see that part of code)

- create sled pin definition
- G28 Works with sled

Serial wait

- Make thermal protection for all hotends and/or bed into simple
switches
- Now enable `WATCH_TEMP_PERIOD` when `THERMAL_PROTECTION_HOTENDS` is
enabled
- Move detailed thermal parameters to `Configuration_adv.h`
- Add sanity checks to warn about old configurations
- Change `WATCH_TEMP_PERIOD` to seconds instead of milliseconds

More thermal protection

replace some bools