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

Fix: increased debounce delay.

Replaces #145 which is way out of date

Czech language translation.

Added comment for Czech language (associated with file language_cz.h).

(PR #138)

When the ISR does not finish in time, the timer will
wrap in the computation of the next interrupt time.

This hack replaces the correct (past) time with a time not far in the future.

As noted in #130 allen key probe stow rate is based on homing rates,
but homing rates were left out of most delta configs. This unifies the
XYZ homing rates and applies the unified rates to allen key movements.

As noted by @o-lampe at https://github.com/MarlinFirmware/MarlinDev/issues/114#issuecomment-136757614 the `MANUAL_FEEDRATE` for Delta Z should be the same as XY.

Added my name following naming convention.

Fix a compile error introduced in #98

As noted in #133 you can’t disable `SDSUPPORT` with `MAKRPANEL`,
`PANEL_ONE`, `MINIPANEL`, or `ULTIPANEL`. This patch makes it possible
to disable `SDSUPPORT` on these controllers and then disables it by
default.

Users of these controllers will now need to enable `SDSUPPORT` in their
configurations as others currently do.