Update gcodetools_tools_library.inx

Added a new tool, called plotter
Update gcodetools.py

Added a new tool, called plotter
Added an option to choose the type of comments for gcode, ( or ;
Create README.md
Update README.md
Update README.md
Update README.md
Merge pull request #2 from furanshishouco/master

New plotter tool and type of gcode comments