fixed problems with joined inheritance and composite keys

SchemaTool now creates all Id columns not just only the first one.
Insert statement for child entity now contains parameter for additional key columns only once.
inheritance with composite keys

added tests for single table inheritance
Adding EntityManagerDecorator base class as an extension point for EntityManager
indexby metadata column
missing new line
indexby ddc117 tests
no lang
cascade remove persist on links
[DDC-2426] Missing length attribute in doctrine-mapping.xsd for <id> tag.
Merge branch 'DDC-2426'
[DDC-2267] Allow EntityManager#flush($entity) to be called on entities scheduled for removal.
Merge branch 'DDC-2267'
Merge pull request #537 from Powerhamster/joined-composite-keys

fixed problems with joined inheritance and composite keys
Merge pull request #524 from lstrojny/feature/entity-manager-decorator

EntityManagerDecorator base class as an extension point for EntityManager
Swapped places indexBy and condition in accordance with EBNF
Added test complex inner join with indexBy
Add documentation to EntityManager about instantiation, decoration over inheritance, and some generic introduction.
[DDC-2423] Fixed bug with EntityGenerator not generating fetch="" attribute in association annotations.
Merge branch 'DDC-2423'
Merge branch 'DDC-2437'