Delta auto-calibration updates

Configuration cleanup

Right now G26 doesn't send a notice to the host that it's running.  It's
not until the heaters are at temperature that you know for sure if it's
running or not.

Added host temperature prints so that someone watching the host
interface will see the temperatures change during the warm up period.
Updates are sent every 5 seconds.

Endstop not enabled if pin is zero

Various cleanups for recent merges

PlatformIO-related improvement

Also added the new .pio-related directory to .gitignore, and a few ignores for those who use cmake.

* Correct over optimization of pre-initialized variables

NEAR_ZERO() works most of the time...  But it leaves corner cases
uncovered.  We need to explicitly check if these variables are +/-
infinity.

* Correct over optimization of pre-initialized variables

This is what I did yesterday:

- basicly gave the tests more comprehensive names; put all the
declarations at the top; got rid of the magic negative C-value (renamed
to P + A, O, T)

- "cos(RADIANS(180 + 30 * axis)) * (1 + circles * 0.1 * ((zig_zag) ? 1 :
-1)) * delta_calibration_radius" compiles wrong is zig_zag statement is
without brackets

- DELTA_TOWER_ANGLE_TRIM reset to 3 values (the calcs use the 3th value
to normalize will not compile otherwise)

-Wrote 3 dummies to keep EEPROM lenght the same

-Reset the configs to the 'original' with autocal + menu disabled (but
can be enabled of course)

Last three Spanish language strings

Updates as per @thinkyhead request.

As proffered in #6252

Update language_de.h

* Update language_cz.h for new translations

* Correction translate

* Revert correction back to hotend

Adding missing strings to Spanish language, as per changes recently
done to the RCBugFix branch.

updated the RCbugfix release with additional Dutch translations

The first character in the string wasn't blanked if the number went from >= 100 to <100, resulting in artefacts in the displayed string.

M666

+ tower radians absolute value

The Configuration.h file entries for BL-Touch have been updated to:
```cpp
//#define BLTOUCH
//#define BLTOUCH_DELAY 375      // (ms) Enable and increase if needed
//#define BLTOUCH_HEATERS_OFF // if defined the printer's heaters are
turned off during probe event
```

The electro-magnetic interference from the bed and nozzle are affecting
the BL-Touch repeatability for some users.   This problem can be helped
by shutting down the heaters during the actual probe event and then
quickly turning them back on.

Because this code is messing with the heaters, it is written in a
paranoid manner.  It only turns the heaters back on if everything is
EXACTLY as it expects things to be.  The BL-Touch probe must have been
put into a deployed state less than 20 seconds prior, or the stow()
function will NOT turn the heaters on.

This code has been tested and works for both G28 and probing functions.

Giving a negative number of probe points disables the tower angle
correction calibration ('4point' instead of '7point' solution)

EEPROM version updated

Also setting up Z-Probe on the machine.