change OPPS_CORE_APPS location, add in opps.core
remove OPPS_CORE_APPS, add on INSTALLED_APPS list
Fixes Container publishable manager
Merge pull request #344 from mauler/stable/0.2.5

Fixes Container publishable manager on 0.2.5
Adds Container unique_together validation on form
Adds missing param slug validation
Removes duplicated code on search_indexes
Fixes TagList view SearchQuerySet models chain
Merge branch 'bugfix/0.2.x'

Conflicts:
	example/example/settings.py
	opps/__init__.py