add support for null event and couple of new usages

nullevent is an event that can happen in the steam but we want to skip
it.

added two sample events like that: INTVAR_EVENT and GTID_LOG_EVENT -
those are events that happen when we do GTID enabled replication, but
are of no use (at least not for me at this time) in this packages
aspect. It might be when we support moving to a different master
seamlessly.
changed null event name to NotImplementedEvent
change names of events to V2 from default

according to this post
http://dev.mysql.com/doc/internals/en/row-based-replication.html#rows-event
events are marked as version 0,1,2 (current) - the code had _V1 and no
version at all - I think it would b easier and morefuture compatible to
use V2 since it seems V3 is unavoidable.
Merge pull request #22 from liorsion/remote_master

Added NotImplementedEvent for a few events that we currently don't need
Add Lior Sion to contributors
Merge branch 'rename_event_version' of github.com:liorsion/python-mysql-replication into liorsion-rename_event_version

Conflicts:
	pymysqlreplication/row_event.py
	pymysqlreplication/tests/test_basic.py
Update event.py

Remove ```log_persistancer```, which is currently not supported in UPSTREAM.
wrong inheritance name

bad copy & paste, sorry.
Merge pull request #25 from liorsion/patch-1

wrong inheritance name
coding style refines.

to fit PEP8 standard.
Merge branch 'master' into lxyu-coding_style_refine

Conflicts:
	pymysqlreplication/event.py
Add MySQL Hadoop Applier
Cleanup
Fix Python 3 support
add feature to start stream from postion
allow stop event.
add log_pos tests
Add Lyx Yu to contributors
Merge github.com:noplay/python-mysql-replication

Conflicts:
	pymysqlreplication/constants/BINLOG.py
	pymysqlreplication/event.py
	pymysqlreplication/packet.py
re-adding gtid related events