Bencoder.pyx

+ Add support for Python 3.8
+ Drop support for Python 3.4

+ Use built-in dict instead of OrderedDict on Python >= 3.7
+ Drop support for Python 3.3
+ Fix bytes parsing when used with python-future 41

Drop support for Python 2.6
Performance boost for bencode method. 7

Add bdecode2 method. 6

- Performance Improvement
- Fix package metainfo ( https://github.com/whtsky/bencoder.pyx/issues/3 )

Support encode large int.