Moving 'return -1;' directly below the conditions improves readability
and also better represents the coding style of other functions in
crypt_core.c (and everywhere else).
This typo doesn't seem to cause any issue because according to the
code in vanilla NaCl the first crypto_box_ZEROBYTES (for encryption)
and crypto_box_BOXZEROBYTES (for decryption) of the array passed to
the crypto_box*() functions don't need to be zero for it to work.
The documentation however clearly states that they need to be zero
which means they need to be zero.
Fixed circular dependency between DHT and net_crypto: DHT no longer
depends on net_crypto.
Moved the crypto request packets functions to crypto core and DHT.
Cleaned up/added some defines that can be used to get the true maximum
length of things like the friends request message.
MAX_DATA_SIZE has been replaced in most places by more appropriate defines.
Moved Bunch of functions from net_crypto to crypto_core.
decrypt_data_fast and decrypt_data_symmetric were the same thing
therefore, removed decrypt_data_fast.
Replaced all the crypto_secretbox_* defines with the equivalent
crypto_box_* one.
New define: crypto_box_KEYBYTES that is equal to
crypto_box_BEFORENMBYTES.
codedust