application: Remove unused signals and methods
Move the gitignores to a single file
bin: Make sure we use python2 when python3 is the default
Remove retired maintainer from the DOAP file aimed at packagers
Remove obsolete svn file
pipeline: Raise an exception when setting the timeline fails
pipeline: Simplify logging of obtained duration value
project: Add the aspect_ratio dynamic property
tests: Allow the tests to be run by frameworks like nosetests
mainwindow: Reuse in_devel from configure
mainwindow: Make the version display more robust in the about window

Also add a unittest for the latest version logic and
moved the Pitivi tests to test_application.py because
that's the module where the Pitivi class resides.
mainwindow: Remove unused variable setting logic
mainwindow: Close the previewer only when the user pressed ESC or Q

The main problem was that if the user tries to click the playback bar to
play at a different position, it happens too often to get the mouse
cursor outside of the window and then the dialog was closing.

- Also allow using SPACE to toggle playback.
- Also moved the preview UI logic to a new PreviewAssetWindow class.
render: Allow the render progress dialog to close the desktop notification

This got broken in 38861f742af4ce115c9265f3e7c85d8ea0f17111
configure: Rename constant name to be uppercase
widgets: Handle smooth scroll events on the zoom slider
widgets: Simplify the zoom controls logic

- Made the UI callbacks as thin as possible.
- Get and set the zoom level by using Zoomable directly instead of
  through the _zoomAdjustment field.
- Got rid of the _updateZoomSlider hack which at this point became
  obsolete.
- Got rid of the zoomed_fitted field because it was not used anywhere.
- Removed the timeline._scrollToPlayhead() because it does not make
  sense to do that when the zoom level is changed.
timeline: Make sure the zoom level is always an int
widgets: Use the zoom slider tooltip to display the duration of the displayed timeline
elements: Remove code with no effect