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

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.

- Address #1262 by leaving values as set
- Rename `add_homing` to `home_offset`

by updating 'encoderPosition' in END_MENU() line 1.

- Add `Conditionals.h` with calculated configuration values
- Add `SanityCheck.h` with checks for configuration errors
- Remove equivalent code from all configurations
- Move error checks from some sources to `SanityCheck.h` also
- Fix initialization of count_direction in stepper.cpp

When one hit "Stop Print" option in LCD menu, the command buffer was not
cleared. The printer keep moving until the buffer has been emptied.
Actually I could not clear the command buffer as well.. I don't know
why, it doesnt work as expected.
I need to implement a routine inside Stepper ISR to handle such
situation.

got:
ultralcd.cpp:408: warning: 'void lcd_autostart_sd()' defined but not used

Got:
ultralcd.cpp:64: warning: 'void lcd_control_retract_menu()' declared 'static' but never defined

While bunting an other bug I stumbled across:
ultralcd.cpp:1250: warning: comparison between signed and unsigned
integer expressions
Changed to the type of lcd_next_update_millis.

- Get rid of _selected functions, passing selected state instead

- Add BIT and TEST macros
- Add _APPLY_ macros to stepper.cpp to help with consolidation
- Consolidate code in stepper.cpp using macros
- Apply standards in stepper.cpp
- Use >= 0 instead of > -1 as a better semantic
- Replace DUAL_Y_CARRIAGE with Y_DUAL_STEPPER_DRIVERS

Added option to set Travel Acceleration (non printing moves).
The M204 options was a non sense (S for printing moves and T for retract
moves).

It has been changed to:
P = Printing moves
R = Retract only (no X, Y, Z) moves
T = Travel (non
printing) moves

I will add this info o G-Code wiki in reprap.org. I also advise to put
this info in Marlin next version changelog.

The encrot values are used in only one place, and don’t vary, so remove
redundant references.

- Fix bug in lcd_control_temperature_menu
- Remove test menu-item left in from multi-line command feature
- Replace literals with translatable strings
- Reduce lcd_preheat code redundancy
- Reduce menu macro redundancy
- Clean up formatting

Last commit before bed.

- Make this work per #1344

Introduced lcd_strlen() and lcd_strlen_P().
Replaced the old functions where necessary.
Reworked language_ru.h.

Speeded up test for zero length string in cardreader.cpp

Prework for issue #1448 and #1447

Will merge in when pull request #1457 is in.

Fix number of nozzle displayed in temperature menu.

This won’t reduce the string storage in the end, but it makes the
language files smaller. Also removed remaining unused strings.

Replace instances of the number 13 with FILENAME_LENGTH where
appropriate.

Replace instances of the number 13 with FILENAME_LENGTH where
appropriate.

* Adds config parameter `PID_PARAMS_PER_EXTRUDER` - allows single PID
parameters to be used where this would be preferable (e.g. dual
identical extruders)
* When disabled, will use `float Kp, Ki, Kd, Kc;` as before.
Preprocessor macros used to switch between.
* ultralcd.cpp defines extra menus for extra parameters only where
required
* M301 reports `e:xx` only if independent pid parameters enabled
* EEPROM structure still leaves space for 3 extruders worth, when undef
will save single parameter to all extruder positions, but only read the
first
* Switching off saves approx 330 B with no LCD enabled, 2634B with LCD
(RRD) enabled: this is significant.
* LCD modifications should be tested.

* Depending on extruder count, will add menu items for ultralcd to edit
individual PID parameters for each extruder
* Added menu items to each language_xx.h
* Builds OK, but recommend testing with typical LCD

Small changes (and formatting to confuse the diff’er) which first
allows DOGLCD and LCD_PROGRESS_BAR to be enabled in tandem, then a
#warning (rather than error) that the extra progress bar / message
options don’t apply to graphical displays at this time. This leaves
open perhaps combining the progress bar and message area in some future
(or forked custom) graphical LCD display arrangement (at which time the
relevant variables may be moved into ultralcd.cpp with externs in
ultralcd.h). I also added a conditional error that the progress bar and
the filament display may not work well together.

This reverts commit dd7e4ee97f.

This reverts commit 2b9722f387.