- also by default use ${HOME}/Arduino as install directory which may be more
sane, especially with arduino packages provided by distributions
- bump arduino version to 106 (this seems to be useless)
- program firmware through the USB serial which is more comfortable way how
to program the firmware
- use 57600 programing speed by default which seems to be more reliable
with arduino bootloaders (at least with those shipped with the Melzi2 boards)

Signed-off-by: Jaroslav Škarvada <jskarvad@redhat.com>

by alternate definition for the callback macros

Move slow_buttons_update into the LCD_UPDATE_INTERVAL block
lcd_implementation_read_slow_buttons() will then be executed ~10 times a
second.

This is a back port of the correct in issue #248

Analog to https://github.com/MarlinFirmware/MarlinDev/pull/250 by
@RicardoGA

Restore the Babystep Multiplicator functionality and now it's available
for X/Y/Z

For now Z_MIN_PROBE_REPEATABILITY_TEST is not possible for DELTA or SCARA
configurations.
This PR comments the feature out, where it is commented in by default.

because of hardware differences on the SERVO0_PIN

Tests DELTA, AUTO_BED_LEVELING_FEATURE and ALLEN_KEY

According to #123 negative values for XY at or below -100 are displaying incorrectly, dropping the first digit. Deltas can easily have XY values in this range. This PR adds a function to display floats/ints formatted like `_123`, `-123`, `_-12`, or `__-1` as appropriate and applies it to the XY coordinates on Hitachi displays. It also moves the Z value to the right to be consistent with the XY formatting.

Align strings with release

in language.h, but was not renamed here. If TEMP_SENSOR_1 is enabled as redundant then
an error is thrown that MSG_EXTRUDER_SWITCHED_OFF is not defined.

Originaly by @12dstring

Keep "astyled" reformatting

As noted by @darkjavi et.al. in #103, the E1 motor was not being enabled in planner.cpp when using DUAL_X_CARRIAGE. This patch enables and disables E1 as it should.

Add SDEXTRASLOW which runs the SD card at SPI_QUARTER_SPEED. Quarter speed is needed for RIGIDBOT_PANEL

Fix: increased debounce delay.