Add better date / datetime validation (pull 2)

addition to #631 with update to master + timefield support
Fix for python 3 support - thanks @Linovia
Fix for python 3 support
Add drf settings + output format + testcases
Add docs update - part 1
Add new ISO8601 setting + integration
Update docs
Add better date / datetime validation (pull 2)

addition to #631 with update to master + timefield support
Fix for python 3 support - thanks @Linovia
Fix for python 3 support
Add drf settings + output format + testcases
Add docs update - part 1
Add new ISO8601 setting + integration
Update docs
Merge branch 'datevalidation_2' of https://github.com/minddust/django-rest-framework into datevalidation_2

Conflicts:
	rest_framework/tests/filterset.py
Add format class attributes
Add none testcases to date, datetime, time
Fix for django 1.3 compatibility
Merge datetime formats
Updating docs