PersistSpecific
added error message in support for backend specific values
supporting PersistSpecific on all backends
tested PersistSpecific support for mysql
changed PersistSpecific to PersistDbSpecific
Merge pull request #143 from bogiebro/master

Backend specific datatypes, take 2
ignore cabal sandbox
This commit fixes issue #157
Fixes double precision test.
Merge pull request #159 from jcristovao/doublePrecision

persistent-test double precision
Merge pull request #158 from jcristovao/timePrecision

persistent-test handling of dates in PostgreSQL/MySQL (pullRequest)