- 'string_field' was missing from __all__
 - use operator.itemgetter instead of trivial getter function

 - improve docstrings
 - use the same 'deleter' for all properties
 - new property factory: string_field
 - int_field properties return 0 if the item is not found

And allow plugins to do 'from debexpo.plugins.api import *' (with a
properly defined __all__) instead of importing everything explicitely.

 - Comments, debug messages, cleanup imports, better variable names.

 - nicer code in the ``nb_results`` property (BasePlugin)

BasePlugin:

 - new methods: ``load`` and ``save`` for loading the data and
   committing the sqlalchemy session

 - ``_load_result``, allowing easy overridding in specific plugins' classes (e.g. QAPlugin)

 - ``db_objects`` attribute replaced by ``results``

Plugins class now simpler.

Changes visible in plugins:

 - new decorator: importercmd, for BasePlugin subclasses' method. Make
   the method runnable by the importer for adding new data to the DB.

 - add a module-level variable in the plugin, ``models``, with the
   list of the plugin's models

 - the name of the plugin is passed as an argument to the BasePlugin
   subclass; it is no longer needed to add a 'plugin' class attribute
   in each model and the plugin class

 - new method for QAPlugin subclasses: ``new_test_result``, returning
   an instance of the ``test_model`` class

 - small detail: ``_new_result`` now ``new_result``, since the method
   is called in subclasses

Implementation details:

 - nicer ``run`` method, using the above-described decorator and the
   ``inspect`` module instead of the former ugly ``test_*`` method
   discovery

 - new methods, ``_load_model`` and ``_load_models`` for processing
   the model list defined in the plugins. Easily derived in specific
   plugin classes (for example, in QAPlugin)

Comments and cosmetics. Add ``Base`` in debexpo.model.meta.__all__.

 - Importer._run_plugins method needed to call load_plugins
 - Plugins.run_plugins now using the ``plugins`` attribute with
 loaded instances
 - ugly but temporary workaround in BasePlugin.run because of properties
 whose name starts with 'test_'

 - no longer a class method
 - 'render_args' keyword argument for use within subclasses
 - template-finding code moved into new method _find_template (might
   be needed in subclasses)

(comments, docstrings, missing imports, debug messages, breaking too long lines).

Status: working but ugly and not flexible enough.

 - run() only calls test methods
 - new db_objects property for accessing the results after tests have run

* Change copyright header
* Remove PPA controller
* Remove static HTML hooks we don't use anyway

* Change copyright header
* Remove PPA controller
* Remove static HTML hooks we don't use anyway