update changelog and __init__ for 0.16.0
MODIFY
ChangeLog
ChangeLog
+2017-10-31 version 0.16.0
+* Improve write performance with customized cython (@barrywhart in PR #114)
+
2017-10-31 version 0.15.0
* Remove Python 2.6 support (@scottbelden in PR #110)

MODIFY
fastavro/__init__.py
fastavro/__init__.py
@@ -43,7 +43,7 @@ The only onterface function is iter_avro, example usage::
writer(out, schema, records)
'''
-__version_info__ = (0, 15, 0)
+__version_info__ = (0, 16, 0)
__version__ = '%s.%s.%s' % __version_info__

update changelog and __init__ for 0.16.0