First part of DHT hardening done.

Added crypto to the DHT communications.

This defeats completely the first attack mentioned in
docs/DHT_hardening.

Also updated the build system to build the latest test (it links it with
libsodium)
Build fixed?
Build fixed?
If someone wants to fix the cmake, go ahead.
Fixed cmake and Travis
Merge pull request #31 from nurupo/master

Fixed cmake and Travis
Removed useless XML parser.
Added something to DHT_hardening.txt
NaCl moved to other repo.
Simple boostrap server added.
Added conversion from friend_id to client_id
Merge pull request #33 from nurupo/master

Added conversion from friend_id to client_id
Fixed 2 small mistakes present in the last pull request.
Added ncurses tox client
Added doMessenger() to the loop and connecting to the bootstrap node
Merge pull request #36 from ollieh/ncursesclient

Ncursesclient
Cmake changed, small change in random_int()

Cmake builds now builds the new ncurses test only on non windows.
Added FAQ
ncurses test doesn't work very well. Putting back the old test.
fixed the ncurses client i believe