raise error for acts_as_paranoid on models without primary keys

see https://github.com/radar/paranoia/issues/169
Merge pull request #178 from bluej100/require-primary-key

raise error for acts_as_paranoid on models without primary keys
Bump to 2.0.3
Add paranoia_scope as named version of default_scope
Revert "raise error for acts_as_paranoid on models without primary keys"

This reverts commit 6881e750aba90fe205fe3a91b4ed92067227dfd5.
test: Rename connect! to setup!; use ensure

Change connect! to setup!, so that we can use connect! to give us an
empty DB with no tables.

Use ensure where appropriate to ensure that tests after that one can run
even if it fails.
Test using acts_as_paranoid class without DB

Regression from 6881e75

We need to be able to load our class definitions without having an
available database connection.
Simplify default_sentinel_value
Revert "Simplify default_sentinel_value"

This reverts commit 4004bd5e3aa11b534903ed824370f1d0b645a17d.
Merge pull request #184 from nyjt/rails4

Add paranoia_scope as named version of default_scope
FIX: where("association_id", id) leads to invalid statement in postgres. where should just be given a hash.
test for issue #185
Slightly more readable spec

Change-Id: Ib73e43a5adcb8bd9b5bbf5b7ca60f9865e5415e7
Add CHANGELOG
Cleanup CHANGELOG formatting
Bump to 2.0.4
Merge upstream/rails4, fix conflicts