python3 compatibility issues

Bug-Url: https://github.com/svinota/mdns/issues/9
Merge pull request #10 from titilambert/master

Fix compatibility with python 3.4.0 on sailfish OS
utf-8 errors under python3

Bug-Url: https://github.com/svinota/mdns/issues/11
decode bytes in dict_to_text()
Cleaning and fix utf-8