Sort authors/maintainers for correct email assignment (#492)

The PackageTemplate class internally sorts the authors and maintainers
by their names.  To ensure that email addresses are later assigned to
the correct names, also sort them in the main function.

catkin_tools/verbs/catkin_create/cli.py

@@ -117,6 +117,15 @@ def main(opts):
     try:
         # Get absolute path to directory containing package
         package_dest_path = os.path.abspath(opts.path)
+
+        # Sort list of maintainers and authors (it will also be sorted inside
+        # PackageTemplate so by sorting it here, we ensure that the same order
+        # is used.  This is important later when email addresses are assigned.
+        if opts.maintainers:
+            opts.maintainers.sort(key=lambda x: x[0])
+        if opts.authors:
+            opts.authors.sort(key=lambda x: x[0])
+
         for package_name in opts.name:
             print('Creating package "%s" in "%s"...' % (package_name, package_dest_path))
             target_path = os.path.join(package_dest_path, package_name)