Issue #397: Display the currently open measurement file name in the top menu of Valentina (dismine/valentina)

New issue 397: Display the currently open measurement file name in the top menu of Valentina https://bitbucket.org/valentinateam/valentina/issues/397/display-the-currently-open-measurement

Susan Spencer:

Display the currently open measurement file name in the top menu of Valentina

This will help users to better understand what they are doing and confirm that they have the correct meausurement file open.