Laboratory's readme.
Fixes #988. Fixes #804. Message::body removes empty values before encoding.
Fixes #988. Fixes #804. Again, but simpler and doesn't break other stuff.
Merge branch 'master' into dev
Allowing explicit related models to be service located.
Resolves the issue in #460
Merge pull request #993 from joebeeson/460-mysql

Resolves the issue in #460
Skip tests which require Mongo if Mongo is not installed.
Merge pull request #994 from jails/refactor/make-mongo-optional-for-tests

Skip tests which require Mongo if Mongo is not installed (close #991).
Add missing mock file.
HABTM Model relationship support for READ queries using `Database` datasources.
Save relations implementation.
Add `lithium\data\Entity::__unset()`.
Merge branch 'patch/readme'
Merge branch 'patch/laboratory'