#5 custom filelist per hub

[Anonymous]

The "settings -> sharing -> sharing directory" directory tree should be altered to "tabs panel", with one fixed "Default" tab.
"Add filelist" and "Remove filelist" buttons to add/remove tabs.
"Add filelist" button should open combobox with hub names (except those already added to tabs) to select from.

For implementation simplicity, the "Default" share could be made a superset of all the hub-specific sublists: all the other tabs would show a (simplified) directory tree composed _only_ by directories shared already in "Default". SubFileLists would then be created by mere "references" to the "default" filelist.