0.7.1

• Improved tests
• PEP8-style formatting
• Unittests: Counter, modes (but not results of them!), test vectors
• [BREAKING CHANGE] Counter class is now in xtea.counter
• Python 3.3 is not tested anymore on Travis CI
• [BREAKING CHANGE] CFB mode is now correctly implemented.
  By setting partition_size it is possible to set the
  internal partition size (in bits) as per PEP-272.
• Python 3: An optional C extension improves speed upto a factor of 10.
• [BREAKING CHANGE] block_size and key_size is now in bytes.
• Skipped 0.7.0 with broken changelog