Added "readOnly: true" to YAML reference

The readOnly configuration is documented nowhere except in the annotations reference.

I added it to the example, for a lack of a better place. But at least it will be documented somewhere.

Can you also confirm that this is correct? I'm starting to use it, and I can't find a way to have doctrine validate it is really working. Even with the metadata validation tool, it won't raise an error if I put an invalid entry (`readOnlyFOOBAR: true`) or an invalid value (`readOnly: FOOBAR`), so I'm kind of blind here.
Test EntityManager::createNamedQuery.
Test EntityManager::createNamedNativeQuery.
XCache cannot be cleared on CLI (like APC)
XCache cannot be cleared on CLI (like APC)
XCache cannot be cleared on CLI (like APC)
Doctrine 2.4 now supports SQLite ALTER TABLE
Merge pull request #872 from matheo/patch-1

Doctrine 2.4 now supports SQLite ALTER TABLE
Add missing LICENSE of documentation
Try running unit tests on HHVM
Add allowed failures for HHVM.
Merge branch 'GH-873'
Update CONTRIBUTING.md
Fixing wrong key for allowing HHVM failures
Merge pull request #876 from doctrine/hotfix/hhvm-allow-failures

Fixing wrong key for allowing HHVM failures
Add failing test for DDC-1787.

Using joined table inheritance, when persisting multiple new entities
that are subclasses of a baseclass that has the @Version attribute set,
only the last persisted entity will have it's version set.
Adding tests that confirm that DDC-2844 is fixed
Adding tests to verify that dql aliases in criteria are correctly converted
Fix DDC-1787.

Credit goes to Jack van Galen for fixing this issue.
Fix for JoinedSubclassPersister, multiple inserts with versioning throws
an optimistic locking exception.
Merge pull request #875 from doctrine/DDC-2844

Adding tests that confirm that DDC-2844 is fixed
Merge pull request #842 from TheFrozenFire/tests/query-tests

Added EntityManager query creation tests