loadRepositoryDatabase(): check if repositoryName is a string
generate_depends_tree(): fix issues with system packages dependencies resolution (like sys-kernel/linux-sabaupm=
PackageSettings:
- on repos_system_mask_installed key, pull all the available idpackages using multiMatch, which seems better
- repos_system_mask_installed_keys: add helper dict to ease interaction
git-svn-id: http://svn.sabayonlinux.org/projects/entropy/trunk@2750 cd1c1023-2f26-0410-ae45-c471fc1f0318