Fix examples module name
Move core test classes into test sub-modules

Test classes was in the same module than their tested classes, so some visbility
errors couldn't be catch.
Move them into sub-modules test :
 - org.ow2.chameleon.fuchsia.core.{declaration -> declaration.test}
 - org.ow2.chameleon.fuchsia.core.{component -> component.test}
Improve ImportDeclaration integration tests
Fix bug in DeclarationBuilder
Move constants from ImportDeclaration to Constants
Fix 2 bugs in DefaultImportationLinker
Add integration tests for DefaultImportationLinker