Singleton instance attribute is now private (use call to get it)
Add PluginManager
Add plugin manager tests and fix some bugs
Test plugin proxies and adding plugin dynamically
Remove extraplugins, add doc
Add debug classes
Fix logger syntax error
Fix bug when pluginmanger debug mode == 'loading'
Split PluginManager in two parts:
  - PluginManager
  - PluginInstanceManager (temporary class, must be improved)
Plugin Instance are now managed using services
Add missing plugin service module.
proxy_class parameter is renamed to plugin_proxy
Merge pull request #88 from gbaty/plugin_manager

Plugin manager
Replace hack to detect 2nd iteration in LPyModel "step" method
Test new model
Improve NewPythonModel compatibility with previous PythonModel
Fix test bug: Empty control manager to avoid control to be shared among tests in test suites
Add documentation
Add PythonFile class (PythonModel file counter part)
First draft for LPyModel using new Model class
NewLPyModel OK
Add model service to create Model class depending on mimetype or dtype.
Project.get_model now returns NewModel class.
You can still use Project.get_filemodel to get old FileModel classes