Added Greek translation of help
timeline: Make scrolling with the mouse wheel on the ruler work again
timeline: Add some initial debugging statements and cleanup code
autoaligner: Make the auto-alignment feature slightly more robust

- Don't stay stuck with a modal progress window when something fails
- Remove the check for numpy, as it is now a hard dependency for waveforms
- Use a larger default window width (like the render progress dialog)
- Remove the window title icon and give the window a proper modal look
Make the import filechooser dialog modal so that it works in fullscreen
project: Prevent the backup restore dialog from being titled "pitivi"
timeline: Resurrect the "Save screenshot" feature

It was collateral damage from the Clutter timeline port.
This brings it back from how it was in commit 6211f3a3e9.
pitivi-git-environment: Add more workarounds to prevent blocking builds

These are only temporary workarounds. GStreamer folks don't seem to be
in a hurry to fix those minor issues and life is too short to keep wasting time
manually resetting my checkouts to prevent the build script from failing.
mediafilespreviewer: Fix the icon shown when previewing audio files
medialibrary: Handle multiple sizes for fallback icons when there are no thumbs

This prevents having minuscule icons in iconview mode and having the columns
resize when clips with thumbnails are added to the iconview.
medialibrary: Support the new "large" (256 pixels) thumbnails

We only need 128px and 64px thumbnail sizes in Pitivi, but as of GNOME 3.8
there's no guarantee that "normal" (128px) versions are generated anymore.
Properly parent the "Render" and "Project Settings" dialogs

This ensures they stay on top and that they work even in fullscreen mode
Refactor project.py and render.py to have cleaner init methods
timeline: Fix splitting clips depending on the selection

Fixes bug #705501
Updated Czech translation
Updated Polish translation
Updated Slovenian translation
Use yelp-tools instead of gnome-doc-utils

Fixes bug #687563
Keep "ghelp" URIs for launching locally (see bug #706223)
Add the autogenerated yelp-tools .stamp files to .gitignore
Added Lithuanian translation