Removed define that could become confusing.
Adding encrypted data to send/getnode packets part 1.
Added symmetric crypto functions to net_crypto.
Astyled some files.
Adding encrypted data to send/getnode packets now done.
Removed now useless ping_id from send/get node packets.
Fixed build error with libsodium.
Base of hardening stuff.
Added some hardening functions to test get nodes.
Removed some now useless code.
Merge branch 'master' into harden

Also removed some old, useless loading code.
Testing requests are now sent.
Get node testing response packets are now handled.
Merge branch 'master' into harden

Conflicts:
	toxcore/DHT.c
Added more printing to DHT_test, fixed typo.
Fixed small issues.

DHT_test now only prints non zero entries.
Fixed test.
Nodes now only send good nodes (or the node that was specifically asked for).
Merge branch 'master' into harden
Try to replace not tested/possibly bad nodes before good nodes.