libpacman: Simplify Database::remove_pkgfromcache removal code.
libpacman: Remove now unused code.
libpacman: Make fset a little bit more correct using 'using' keyword.
libpacman: Add a basic graphing class (still unused) to store relations with package names with the *providers* of the said names.
libpacman: Drop _pacman_pkg_delete.
libpacman: Extract refcounting aspect to a separated class of flib::object.
libpacman: More package/package_node initialisation rework.
libpacman: Move events firing for dependency resolution to trans_t::resolvedeps method.
libpacman: Move acquire/release static version of refcounting helper inside of the class (to avoid namespace polution).
libpacman: Add flib::refcounted_ptr.
libpacman: Fix typo.