Fix for Meshpositions if printer has negative endstop positions

Delta auto-calibration updates

Configuration cleanup

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