Fix Travis build

.travis.yml

@@ -9,7 +9,7 @@ addons:
     - python-pip
 
 install:
-  - pip install --user pytest ecdsa
+  - pip install --user pytest ecdsa curve25519-donna
 
 script:
   - make

CMakeLists.txt

@@ -2,6 +2,7 @@ cmake_minimum_required(VERSION 2.6)
 
 set(SOURCES address.c aescrypt.c aeskey.c aes_modes.c aestab.c base58.c bignum.c bip32.c bip39.c ecdsa.c hmac.c nist256p1.c pbkdf2.c rand.c ripemd160.c secp256k1.c sha2.c ed25519-donna/ed25519.c sha3.c)
 include_directories(ed25519-donna)
+include_directories(curve25519-donna)
 
 # disable sequence point warnings where they are expected
 set_source_files_properties(aeskey.c PROPERTIES