Fixed the tests

Fixed one of the tests

Added two more tests and one more feature

An option has been added to draw open or closed figures. When this 
option is off, the last point and the first point will not be joined or 
else they will be joined

Some major changes -

1) Fixed some problems with the point system
2) Added a dialog for choosing where to save the graph

Added a button for showing the distances between different points

The button shows up inside 'Extra Info' dropdown

Merge branch 'main' of github.com:sumagnadas/graph-plotter into main