Require more recent version of Pint
Proper handling of unknown Class/Subclass/Protocol in usb.
Created lantz.utils sub-package. Added helper for Qt.

Qt components (QtCore, QtGui and QtSvg) are now loaded from
lantz.utils.qt.

This module also defines MetaQObject (a base type for types)
and SuperQObject (a QObject that implements super() right).

The core of this modules are copied from IPython.
Changed Driver to use QObject.
Removed unused Signal Class
Fix for pep8
Improved Signal / Feat / Action in derived class
Added a Default UnitRegistry to Lantz
Started module to create lantz apps and moved start_test_app to it

The App class allows easy to create and use applications with and without GUI. The goal is to have reusable, embeddable and subclassable apps.
Adjusted tests to new behaviour. Now subclasses show parents feats and actions.
Removed all Qt handling code.
Adjusted import for start_test_app.
Changed method name to avoid conflict with Driver.recall
Adjusted imports
Fixed naming: loadUI is now loadUi
Renamed variable to qapp for consistency
Create app module to simplify the creation of CLI and GUI applications.

The module provides two classes: Backend and Frontend to encapsulate the
logic and the user interface respectively of an application.

It additionally deals with threads trying to help users make a responsive
GUI.

It additionally provides two helper functions
- start_gui_app: takes a backend and fronted and shows the app.
- start_test_app: which use to be in the widgets module.
Examples using the backend-frontend classes
Added the examples from the tutorial
Added dummydrivers class to simplify some examples