Add the Open from Damned Lies(DL) button
A user can view two buttons in the main window when no file is opened. These buttons are namely: Open & Open from DL.
However, if a file is opened, the user can view only the Open button. Thus, a user cannot load files from Damned Lies.
To fix this make the Open from DL button visible when a file is opened. Prompt a user to save an edited file before the open button is opened.
Closes #65 (closed)