Convert version number to variable, add version number to menu item so it can display even when not connected to CNC machine.
fixed a type-o
updated version number to 58
adding version number to logfile
tidy imports

tidy and remove duplicate imports
Added Help menu and About dialog
Capital V
Merge branch 'merge_test' into help_menu

Conflicts:
	cncgc.py
Merge branch 'help_menu' into merge_test