Bases: list
Build set of all files listed in the manifests
Build set of all files from manifests plus all include files from sources
Fetch recursively all modules
Get instance of Module being stored at a given location
Check if every module is already fetched
Add new module to the pool.
This is the only way to add new modules to the pool. Thanks to it the pool can easily control its content
Process the top module without descending to children modules
Set dependencies for all project files