Update after Stephane Seyvoz's review.
Merge pull request #5 from SESA188919/documentation

Documentation
Document review : Modify Singleton (gain) and mention unused factory elimination
Merge pull request #7 from jtous/documentation

Get J.Tous modifications.
Merge Julien Tous's modifications.
Add synthesis in docbook.
Fix bug in @Single annotation treatment when a component provides
several mixed annotated and not annotated interfaces.
Fixed conflicts