add helper for failing tests in remote control
add command for sorting the list in the remote directory xlet
set default values for sorting configuration
emit helper signal when a user clicks on a column for sorting
save/restore column sorting when searching in remote directory
use first column by default if column in settings doesn't exist anymore
connect to sort signal instead of click
avoid emitting sort signals unnecessarily
QT automatically handles columns that are out of range
sorting must be deactivated when adding items

when sorting is enabled, sometimes items dissapear once you add
them. The doc on QTableWidget says the same thing and that sorting
should be deactivated when adding items.

However, when reactivating sorting, QTableWidget triggers a
sortingChanged event with a column that does not exist. So I put
a small hack in place to check if the column exists before saving it.
Merge branch '4749_remote_directory_sorted'