Make MBL a static class, use lookup for index-to-point conversion

UBL cleanup, optimization

General minor cleanup

Fix makefile errors, cleanup

Show Filament Width on LCD when SD is disabled

Fix delta_angles

Convert feedrate on SCARA from mm/s to deg/s

Incorrect optimizations of data types and ternary operators caused some
issues.

Board A4JP should be SCOOVO_X9H

Use safe_delay to ensure watchdog reset

UBL's maps are cleaner.   And with a 1 value, G29 O 1  will generate a
map suitable to be Cut & Pasted into Excel so a Suface Map can be
generated.

The wait_for_user change totally broke UBL.   But there is stuff wrong
now in the thermal code and/or LCD Panel code.

PWM dithering followup

Fix type conversion issue with echo_command

Adjust bilinear grid in M851

With the the current definition of echo_command I cannot compile RCBugFix (Arduino IDE 1.8.1) with the error "invalid conversion from 'const char*' to 'char*'".  This change resolves that.

Immediate commands take precedence

Enhancement of PWM, with dithering

After wraparound, pwm_count <= pwm_mask holds, thus soft_pwm_X <= pwm_count
guarantees soft_pwm_X < pwm_mask is true, and the heater will be switched
off in the first branch.
Do not evaluate the pwm conditions a second time, this reduces the
instruction count (4 instructions per PWM) and text size (6 byte).

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>

The compiler is not able to reuse the value of pwm_count, but reloads it
on every evaluation, if is stored in a static variable, as it cannot prove
it will be unchanged. A variable with local scope may not be modified from
the outside, so its value can be reused.
Doing so reduces text size and instruction count.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>

If dithering is enabled, the remainder of the soft_pwm_X duty value at
turnoff time is added to the next cycle. If e.g. the duty is set to 9 and
SCALE is set to 2, the PWM will be active for 8 counts for 3 cycles and
12 counts on each fourth cycle, i.e. the average is 9 cycles.

This compensates the resolution loss at higher scales and allows running
fans with SOFT_PWM with significantly reduced noise.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>

A 128 step PWM has 127 intervals (0/127 ... 127/127 duty). Currently, a
PWM setting of 1/127 is active for 2/128, i.e. double the expected time,
or, in general n+1/128 instead of n/127.
Fixes issue#6003.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>

Patch till UBL is integrated with planner-based leveling

The code to print a hex nibble got broke.   SERIAL_ECHO( (char) ) isn't
suitable for its use.

All the changes to get the code into compliance with Marlin coding
standards made UBL sick.   This pretty much gets UBL back up and
running.

Update Marlin_main.cpp

Add MINIMUM_STEPPER_PULSE ability to babystepping