Config confusion

[dennisvang]

The term "config" is used ambiguously:

• it may be a pyupdater.utils.config.Config instance (which is a dict subclass)
• it may be a normal dict representing either the "py_repo_config" object or the "app_config" object from config.pyu (where "app_config" contains the data for the client_config.py file)

This can be quite confusing. For example, PackageHandler.init gets a config argument, which receives a Config instance, which is not stored (only the value of "UPDATE_PATCHES" is stored). The initializer also defines a self.config attribute, but this has nothing to do with the config argument: it becomes a dict with the content of "py_repo_config" (in PackageHandler._load_config).

Some other points:

• the "py_repo_config" object from config.pyu looks like it is only used to keep a patch count. There is a PackageHandler._add_package_to_config method which is called, which adds a "package" member, but I cannot find where that is ever used. Patch only uses the "patches" member.
• The way config is initialized in PyUpdater.init, etc. also looks like it can be simplified.
• If we could replace the custom Config and ConfigManager by e.g. configparser from the standard library, that probably would help a lot (less maintenance).