d/s/examples/*.py: use python3 in shebang.

With python2 deprecation, it should be safe to enforce use of the
python3 shebang everywhere.  Besides, there can be inconsistencies
between distributions, and even system configuration within a single
distribution, on whether to ship python as python2, as python3, or not
at all.

Signed-off-by: Étienne Mollier <[email protected]>

Author: emollier

docs/source/examples/imageWithMetadata.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 """Copyright © 2014 German Neuroinformatics Node (G-Node)

docs/source/examples/multipleTimeSeries.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 """Copyright © 2014 German Neuroinformatics Node (G-Node)
 

docs/source/examples/singleROI.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 """Copyright © 2014 German Neuroinformatics Node (G-Node)

docs/source/examples/taggedFeature.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 """Copyright © 2014 German Neuroinformatics Node (G-Node)