… does not need to be in []

… previous returns

as I am unsure if the ngc_-prefix should be there on this

…ters

…creating texts with values from parameters etc

…erimental

On some processors, MOSI can be driven to the output level before
the clock is enabled. If the first bit is a 1, this can result in
a longer pulse that is interpreted as a high level by neopixels.

This fix maintains the same inter-bit timings, but ensures the
first bit is always 0. (The last bit is already always zero due
to padding for reset timing requirements).

…t, previously value was 0.

Added support for LinuxCNC style (ABORT,<msg>) comment, requires expressions enabled. Terminates gcode program, outputs message and returns error 253.
Added PRM[<setting>] and PRM[<setting>,<bit>] functions to expressions, returns $-setting value or value of bit in integer type setting.
"hardened" flow control code, fixed bug in repeat...continue handling.
Changed signature of grbl.on_gcode_comment event, now returns status code.

…TS, DTR) changes - initially for USB streams.

…sters to onGcodeComment

…turns status-codes itself