Enforce version 1.0 of Gstreamer.
Change switch_to() to the new API.

In Gstreamer1.0 the InputSelector doesn't have anymore the "switch" signal.
This can be found on commit 9c4ce4ae1682 of gstreamer.
sink%d -> sink_%d.
Remove 0.10 code.
Add comment about the 'sync=False' attribute.
Catch errors in the shell and show them.
Add shebang to pipeline.