ngcgui embedded as axis tab

with support for .gcmc (G-Code Meta Compiler) files

The .ngc and .gcmc files can be intermixed with
ini file lines like:

NGCGUI_SUBFILE    = drill.gcmc
NGCGUI_SUBFILE    = wheels.gcmc
NGCGUI_SUBFILE    = star.gcmc
NGCGUI_SUBFILE    = simp.ngc
NGCGUI_SUBFILE    = ""

See the ini file for example details

