[Feature Request] Use DE's File Dialog

[Alexhuszagh]

On KDE (and I'm assuming Gnome, although I cannot confirm currently), Buka's file dialog is very ugly as it uses the naive X11 file dialog by default. For such an elegant and stylish app, this is a major eye-sore by comparison.

To support KDE, you can detect KDE and execute the following lines:

kdialog --getsavefilename /path/to/dir
kdialog --getopenfilename /path/to/dir

I believe you can do the same with GTK (Gnome) and X11 with gtkdialog and XDialog, respectively.

To detect the current desktop environment, you may check the environment variable DESKTOP_SESSION. For example, on KDE, it is set to /usr/share/xsessions/plasma.