Add unittest.

Using [googletest](https://code.google.com/p/googletest/).

Original test vectors:

+ <http://csrc.nist.gov/groups/STM/cavp/>
    - AES128/192/256
    - TDES
    - SHA1
    - SHA224
    - SHA256
    - SHA384
    - SHA512
+ <https://www.schneier.com/code/vectors.txt>
    - Blowfish
+ <http://tools.ietf.org/html/rfc2144>
    - CAST128
+ <https://www.cosic.esat.kuleuven.be/nessie/testvectors/>
    - IDEA
+ <http://www.nsrl.nist.gov/testdata/>
    - MD5
+ <http://homes.esat.kuleuven.be/~bosselae/ripemd160.html>
    - RIPEMD160

-----

Usage:
```
cd tests
make
./tests
```