+ Doxygen configuration

Moved coding-style.md (development document) to /dev:
* /doc should contain how the code is
* /dev should contain how the code should be (as part of “development tools”)

Added README.md to */ containing basic descriptions.
UnitTestHelp rewritten

Documented too.
[ant] <test> should not depend on <clean>
Merge branch 'master' into guimier-context
Documentation of Context and associated classes