Support for datetime

• Support for values of datetime.datetime class
• Removed support for time.struct_time objects

Dictionaries with keys as int

• Support dictionaries with int as key

Encode/decode to/from stream

• Introduce dump and load methods to support streams

Python2 compatibility

• Decoding strings in Python2 manner

Serialize/deserialize objects

Supported types:

• int, float, str, bool
• dict, list
• time.struct_time
• bytes