Update to language_it.h

update to latest rcbugfix

Fix Travis test for FILAMENTCHANGEENABLE

Fix manual move for multiple extruders

Add macros to move servos

No need to check ULTIPANEL with DOGLCD

Heal the watchdog

Clarify names of prepare_move functions

Wrap all items depending on ULTIPANEL

Improves travis buildroot regexp

  manage_manual_move(); -> ULTIPANEL

Closes #3999: Compilation error with BEEPER_PIN -1

Makr the call of   `manage_manual_move() ` depandent of `ULTIPANEL`

Rename some vars to clarify their relationship to acceleration

Update travis to test for ULTRA and DOG LCD options

New feature: Non blocking tone queue

Throw an error in PID_autotune for E < -1

- `per_sq_second` => `per_s2`
- `per_sqr_second` => `per_s2`
- `axis_steps_per_sqr_second` => `max_acceleration_steps_per_s2`

Support inches, fahrenheit, and kelvin

Use memset in mbl.reset to save 58 bytes

This is an update of MarlinDev PR #196.

G20/21: support for switching input units between millimeters and
inches.
M149: support for changing input temperature units.

In support of these changes, code_value() and code_value_short() are
replaced with an array of functions which handle converting to the
proper types and/or units.

Rename some auto/locals to avoid name conflict

Cleanup and naming for number-to-string functions