Probing command gets stuck in hold if several g38.2 are submitted
Ex.
G0 X0 Y0 Z0
G38.2 Z-10 F100
G10 L20 P0 Z0
G0 Z2
G38.2 Z-1 F50
G10 L20 P0 Z0
G0 Z2
G0 X0 Y0
G38.2 Z-1 F100
G0 Z2
Merge pull request #368 from henols/dev

Probing command gets stuck in hold if several g38.2 are submitted
Probing command gets stuck in hold if several g38.2 are submitted
Ex.
G0 X0 Y0 Z0
G38.2 Z-10 F100
G10 L20 P0 Z0
G0 Z2
G38.2 Z-1 F50
G10 L20 P0 Z0
G0 Z2
G0 X0 Y0
G38.2 Z-1 F100
G0 Z2
Added Probing to Mega2560 and fixed Shapeoko2 compile error
Merge pull request #373 from EliteEng/dev

Added Probing to Mega2560 and fixed Shapeoko2 compile error
Comment corrections and function call update.
Major g-code parser overhaul. 100%* compliant. Other related updates.

- Completely overhauled the g-code parser. It’s now 100%* compliant. (*
may have some bugs). Being compliant, here are some of the major
differences.

- SMALLER and JUST AS FAST! A number of optimizations were found that
sped things up and allowed for the more thorough error-checking to be
installed without a speed hit. Trimmed a lot of ‘fat’ in the parser and
still was able to make it significantly smaller than it was.

- No default feed rate setting! Removed completely! This doesn’t exist
in the g-code standard. So, it now errors out whenever it’s undefined
for motions that require it (G1/2/3/38.2).

- Any g-code parser error expunges the ENTIRE block. This means all
information is lost and not passed on to the running state. Before some
of the states would remain, which could have led to some problems.

- If the g-code block passes all of the error-checks, the g-code state
is updated and all motions are executed according to the order of
execution.

- Changes in spindle speed, when already running, will update the
output pin accordingly. This fixes a bug, where it wouldn’t update the
speed.

- Update g-code parser error reporting. Errors now return detailed
information of what exact went wrong. The most common errors return a
short text description. For less common errors, the parser reports
‘Invalid gcode ID:20’, where 20 is a error ID. A list of error code IDs
and their descriptions will be documented for user reference elsewhere
to save flash space.

- Other notable changes:

- Added a print integer routine for uint8 variables. This saved
significant flash space by switching from a heavier universal print
integer routine.

- Saved some flash space with our own short hypotenuse calculation

- Some arc computation flash and memory optimizations.
Fixed spindle/coolant/dwell state check.
Various minor g-code parser fixes.

- Updated the mantissa calculation that checks for non-integer values
and GXX.X commands that aren’t supported. There was a potential uint8
overflow issue.

- Fixed g-code parser bug related to not using the correct modal
struct. G10 P0 not selecting the current coordinate system when a
G55-59 is issued in the same line.

- Fixed g-code parser bug related to not using the correct modal
struct. Target position locations were not computed correctly when
G90/91 distance modes were changed in the same line. It was using the
previous state, rather than the current block.
Added Nomad defaults
Merge commit '8ed8005f6cc11d998b0a3546fc6d64e978d8277b' into dev

Conflicts:
	config.h