Necessary for the Ant task for instance:
- masked packages
- container extensions

=> This part of the API should be improved

=> it is automatically generated from the module Id found in 
   "sonar.modules"

The 2 following properties have been introduced for better 
readability and consistency:
  - sonar.projectBaseDir
  - sonar.projectConfigFile

=> When launching the Sonar Runner, a meaningful error message must 
   be thrown when one source directory doesn't exist