Add support for selecting multiple files

[giswqs]

Currently, ipyfilechooser only allows selecting a single file. Some tools requires a file list (i.e., selecting multiple files). One potential workaround I can think of is to use a SelectMultiple widget and push ipyfilechooser.selected to the widget with register_callback. Related issue: crahan/ipyfilechooser#11

https://ipywidgets.readthedocs.io/en/latest/examples/Widget%20List.html#SelectMultiple

[pawansingh1610]

as in the image above, i wrote all my file names then how to push them to the Whitebox GUI

[giswqs]

whiteboxgui does not support selecting multiple files yet. You will have to use whitebox in a script.