hal_gremlin - Emit signal in case of gcode error

this signal do allow users of glade GUI's to react
to possible gcode errors


Signed-off-by: Norbert Schechner <nieson@web.de>
gmoccapy_1_3_5 - report about gcode errors

ver. 1.3.5
- added the new signal from hal_gremlin to gmoccapy so we do get
  a message of gcode errors when loading a file and not only when
  the interpreter does read the wrong line. A warning box will inform
  about the error details.


Signed-off-by: Norbert Schechner <nieson@web.de>