Split out individual events in the event base.py to their own files

[liquidsec]

Things are getting real crowded in there.

Over 2000 lines with every event type, some individual event types (url_unverified, etc) getting fairly large on their own.

Possible actions:

Split by category (url based events, dns based events, etc)
Individual files for every event

[liquidsec]

@singlerider If you have any thoughts on how this could be broken up