Add two new functions to the crypto library

[wfreda]

I would like to add two new functions to the crypto library. They are:
bool wickr_crypto_engine_encrypt_ofile(FILE *fin, const wickr_cipher_key_t *key, FILE *fout);
bool wickr_crypto_engine_decrypt_ofile(FILE *fin, const wickr_cipher_key_t *key, FILE *fout, bool only_auth_ciphers);

These functions already exist inside the library. This addition would make them publicly available via wickr_crypto_engine.