Modified the original yenc module by Alessandro Duca alessandro.duca@gmail.com
for use within SABnzbd.

The module was extended to do header parsing and full yEnc decoding from a
Python list of chunks, the way in which data is retrieved from usenet. This is
particularly beneficial when SSL is enabled, which limits the size of each
chunk to 16K. Parsing these chunks in Python is much more costly. Additionally,
this module releases Python's GIL during decoding, greatly increasing
performance of the overall download process.