a wrapper around pycares featuring:
 * extended response callback - includes query
 * used sample code to build a class which hides all the socket/boilerplate stuff
 * ptr, A and AAAA query function
 * added missing error code constants
 * store pending requests and results

TODO:
 > an UnicodeDecodeError needs to be fixed
 > setup.py, tests, .. (not a real pyton module, yet)