Implement file lists

File lists can now be used to define several sources to display.

This works close to the list feature of impressive, except that we do
not require an @ character, but instead treat all fiels ending in .txt
as list files.

Lists are scanned recursively, and fiels downloaded to generate the
new lists for impressive, and a final list is passed.

On download, all files are now compared to trigger a reload on change
of any file in the list.

0 files changed, 0 insertions, 0 deletions