Merge pull request #142 from hrumph/master

replaceUnique has list subtraction reversed
PersistSpecific
added error message in support for backend specific values
supporting PersistSpecific on all backends
tested PersistSpecific support for mysql
support embedding of an Entity

This is really for MongoDB.
Also support the ObjectId type via Objectid
fix tests for SQL
run Entity tests against SQL
Revert "run Entity tests against SQL"

This reverts commit 61f0e4e213e0e46322e3479d6106162b18dc2602.

The tests have a weird GHC error.
Merge pull request #144 from yesodweb/embedded-entitites

support embedding of an Entity
version bumps for Entity embedding
changed PersistSpecific to PersistDbSpecific
Fix bug in mkDeleteCascade for MigrationOnly
Fix typos in documentation
Merge pull request #146 from lubomir/doc-typos

Fix typos in documentation
Crappy implementation of a fix to issue #147
Fix missing dependency
Merge pull request #148 from scshunt/master

Crappy implementation of a fix to issue #147
Merge pull request #143 from bogiebro/master

Backend specific datatypes, take 2
ignore cabal sandbox