Adds Python 3 shebangs to command-line scripts.

examples/loadsave.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 """A simple example which loads a SEG Y file and saves it again.
 
 Usage:
@@ -5,6 +7,7 @@ Usage:
     loadsave.py <in.segy> <out.segy>
 
 """
+
 from __future__ import print_function
 
 import os

examples/report.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 """Displays a simple report of a SEG Y file.
 
 Usage:

examples/timed_reader.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 """A simple example which times reading of all traces in a SEG Y file.
 
 Usage:

examples/timeslice.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 """Extract a timeslice from a 3D seismic volume to a Numpy array.
 
 This utility assumes the inline and crossline numbers are evenly spaced.