bulletin board: redesign
bulletin board: compute the list of voters
final server: add cors and smaller fixes
bulletin board: show the summary
add option "useTLS" to the config files of the servers
voting booth: fix the server address

The address of the collecting server was not taken from the
manifest.
bulletin board: fetch the data from the servers
bulleting board: a bit of polishing
[java] fix wrong list of voters in the partial result
bulletin board: convert voter identifiers from bytes