Typo fixes in comments in existing code.

- Also patch up some warnings

- Fix a bug reading `code_value` for `M503 Sn`
- Hide and remove unused variables

- Also a small tweak to SanityCheck.h

- Increase the probe offset range to -20…20
- Apply the range limits to the menu item

/SanityCheck.h:107:53: warning: missing terminating ' character
...

to avoid:
Marlin_main.cpp:1790: warning: array subscript is above array bounds.

- Put + in front of positive values in the output

Don’t set CUSTOM_M_CODE_SET_Z_PROBE_OFFSET if there’s no Z probe

- Init `zprobe_zoffset`
- Remove `current_position[Z_AXIS] = zprobe_zoffset` lines from the
`set_bed_level_equation_*` functions
- Apply standards to `mesh_bed_leveling` files
- Document `MESH_BED_LEVELING`

if not have SDSUPPORT the fromsd array is not necessary

It just probe all the bed without appliying the matrix.
Useful after a first G29 to check the topology.

documentation how to disable buzzer feedback

make it unconditional
remove all definitions in the 'Configuration.h's
remove form 'Conditionals.h'

to make the temperature-code work again with Arduino 1.0.6.

Sorry could not make an extra block on base level.

what caused an extra update of encoderLine most of the time.

Tweak the documentation

ZigZag: Inverted Behavior.. If T supplied, it does not zigzag.
Topograph table: The table was rotated 90º clockwise.

Z_DUAL_ENDSTOPS is a feature to enable the use of 2 endstops for both Z
steppers - Let's call them Z stepper and Z2 stepper.
That way the machine is capable to align the bed during home, since both
Z steppers are homed.
There is also an implementation of M666 (software endstops adjustment)
to this feature.
After Z homing, this adjustment is applied to just one of the steppers
in order to align the bed.
One just need to home the Z axis and measure the distance difference
between both Z axis and apply the math: Z adjust = Z - Z2.
If the Z stepper axis is closer to the bed, the measure Z > Z2 (yes, it
is.. think about it) and the Z adjust would be positive.
Play a little bit with small adjustments (0.5mm) and check the
behaviour.
The M119 (endstops report) will start reporting the Z2 Endstop as well.

This reverts commit e6cb8ee188.

Conflicts:
	Marlin/dogm_lcd_implementation.h
Confilkt solved
Needs rework.

This reverts commit 8c5bb38748.

- Remove test of raw temp for thermistor 0 when using MAX6675
- Longer `raw_temp_value` array for `TEMP_SENSOR_1_AS_REDUNDANT`

I've updated the minimum values from the LCD.
It has been a while that i want to at least fix this.
I have an inductive probe and often i need to set my zOffset to something lower than 0.5.
With the current implementation, the default LCD value is set to 0.5 for some reason.
On my case i need to be able to set it down to 0.0 as my inductive probe can be lower than 0.5.
Before with the LCD we couldn't change this value below 0.5. We had to flash the firmware every time which was painful.
Now we are able to change this value down to 0.0 if needed.
I've also changed the minimum value for Z min acceleration.
In the default configuration it's set to 25 but on the LCD the minimum was 100 which is not coherent.
I've changes the minimum to 10. On this axis, depending on the mechanics/motor drivers we might require very low acceleration, so i guess 10 is somehow realistic.

- Get rid of unused temp states in the ISR, resulting in more frequent
temperature reading with fewer sensors
- Shrink code slightly in min/max testing

- Address issue #1669
- Remove the TOPO_ORIGIN configuration setting