Make "Multiple files" mode editable in "PDF Bookmark Wizard"

[BB_Fan]

Suggestion to make the "Multiple files" mode editable, in order to better direct its impact and considerable power.

Indeed, it is perfectly imaginable that a user wants ONLY the pdf files in the active directory to be processed, instead of also having to foresee what will happen at any subordinate level. Currently, this effect can only be guaranteed when a user gathers all files to be processed in a directory with no sub-directories. It would be handier if he could edit the default setting to obtain the same result. E.g. via a button which opens a tree structure with the current directory and its sub-directories. - every directoy in this presentation would be preceded by a selection box, which is ticked by default. - also, a "deselect all" functionality (button) would be present. - unticking a selection box would imply the corresponding SUB-levels to be excluded from the scope of the Wizard. (the pdf files in the directory itself will still be processed) The easiest way to implement this, is to exclude the "unselected" directory with all its subdirectories. Allowing individual directories to be unselected, i.e. without touching its sub-directories, is probably overkill.

NB: in the above proposal it is assumed that anything displayed in the tree can be processed, i.e. that path length or any special characters can't cause errors. (indeed, the "copy" feature of the Wizard implies that the path length will be extended AND that any character can be used for the copy's name, hence it may be necessary to foresee some exception management)