Initial commit.
Basic plugin loader.
* some basic refactoring
* use better QSingleApplication implementation
* combine tracs Componentsystem (ported to PySide)
  with QtCreator's PluginManager
* etc.
correct IPlugin as interface
bulk
* implemented PluiginErrorOverview
* typos, typos, typos
make PluginManager.hasError a property
Typos
remove test debug printing
corrected IPlugin interface and updated doc
corrected coreplugin interface implementation
removed iplugin as own file
refactoring:
* extensionsystem.components: trac components
* extensionsystem.interfaces: public interface
  for IPlugin
* extensionsystem: rest (PluginManager, PluginSpec etc.)
set default plugin category to 'Generic'
adding Author to pluginspecs
added some pluginspec tests
some refactoring
fix crash when compatVersion string in plugin is empty
fix sys.exit()
* added masses of icons
* completed Id and Context classes inclusive tests
* many other small things(TM)
renamed project to MedScript
deleted unneeded test plugin
git ignore __pycache__