Verify print2file

1. print2file is now a function of MyFig and in myTool so that one can use it in a object oriented manner but also the wrapper.

   • MyFig::print2file has been tested see tests 302,303,304,305,306 and 403

2. a new feature has been added: the user can now provide the path in the filename. It results in ignoring opath.

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remark: printing a figure into a file requires that the MyFig.canvas is modified. Therefore if the figure was bounded to a window, the canvas will be unbound. For this reason MyFig::print2file unbound the figure to any window. As a result we had to add some bounding in MyWin::refresh.