feature request: set dialog title #104

Currently, your API does not allow the title of the file dialog to be specified.

It seems straightforward to support this, because all of the underlying platform APIs provide an option to set the title:

• IFileDialog::SetTitle on Windows
• title property of NSSavePanel on MacOS
• on Gtk and Zenity you are already setting the title to "Open File":

  nativefiledialog/src/nfd_gtk.c

  Line 181 in 67345b8

  dialog = gtk_file_chooser_dialog_new( "Open File",

  and

  nativefiledialog/src/nfd_zenity.c

  Line 190 in 67345b8

  command[2] = strdup("--title=Open File");

PS. Just got a Julia wrapper for this library (https://github.com/Suavesito-Olimpiada/NativeFileDialog.jl) along with precompiled binaries for many platforms (https://github.com/JuliaBinaryWrappers/NativeFileDialog_jll.jl), thanks to @Suavesito-Olimpiada.