Python script shebang cleanup (#37859)

* Use explicit Python version in json tools

These tools used '#!/usr/bin/env python' but required Python 2.  This no
longer works on systems where Python 3 is the default.

Tweak their #! lines to specify python2.

* Remove space from #! line

* Make gfx_tools find python by path

The scripts in tools/gfx_tools were running /bin/python directly.  The
convention is to use /usr/bin/env python, so switch to that.

Also, they were not executable.  Make them so.

* Make Python scripts executable

Some Python scripts had #! lines but were not executable.  Make them so.

tools/gfx_tools/compose.py

@@ -1,4 +1,4 @@
-#!/bin/python
+#!/usr/bin/env python
 
 # compose.py
 # Split a gfx directory made of 1000s of little images and files into a set of tilesheets

tools/gfx_tools/decompose.py

@@ -1,4 +1,4 @@
-#!/bin/python
+#!/usr/bin/env python
 
 # decompose.py
 # Split a gfx tile_config.json into 1000s of little directories, each with their own config

tools/gfx_tools/png_update.py

@@ -1,4 +1,4 @@
-#!/bin/python
+#!/usr/bin/env python
 
 # png_update.py
 # Rename a png and update all references to it.
@@ -154,4 +154,3 @@ def convert_tile_entry_file(file_path, old_name, new_name):
                 os.rename(old_path, new_path)
 
 
-

tools/json_tools/keys.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 """Run this script with -h for usage info and docs.
 """
 

tools/json_tools/lister.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 """Run this script with -h for usage info and docs.
 """
 

tools/json_tools/pluck.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 """Run this script with -h for usage info and docs.
 """
 

tools/json_tools/splitter.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 """Run this script with -h for usage info and docs.
 """
 

tools/json_tools/values.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 """Run this script with -h for usage info and docs.
 """
 

utilities/building-utility/deconstruct.py

@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#!/usr/bin/env python
 '''Tool to combine ascii map cells with json templates.
 
 Original design and implementation: acidia (https://github.com/acidia)