FileDialog

This Extension provides access to open and save dialog classes: OpenFileDialog and SaveFileDialog. Both are non-modal and run asynchronously, so the signals must be used. Other than the name difference (and resulting UI variance) the API for each is identical:

Constructors
- OpenFileDialog
- SaveFileDialog
Properties
- Read Only
  - array(Url) urls: the selected file, as a Url object
  - Url baseUrl, the current path (minus filename) as a Url
  - string file: the selected file, as a string
  - array(string) files: selected files (plural), as an array of strings
- Read/Write
  - Url url: the current Url, can be read from when the user is done or assigned before to set the starting path
  - string filter: a string representing the mimetype filter; e.g. "*.cpp|C++ Source Files\n*.h|Header files" or "*.cpp" or "*.cpp|*h"
  - boolean localOnly: true to show only local files, false if network locations are Ok as well
  - boolean directoriesOnly: true to only allow selection of a directory (not a file)
  - boolean existingOnly: true if only existing files/directories may be selected
Functions
- show(): when called, the dialog will be shown to the user
Signals
- accepted(FileDialogProxy)': emitted when the file dialog has been successfully accepted by the user with one or more files/directories.
- finished(FileDialogProxy): emitted when the file dialog closes, included when cancelled/closed without being accepted