Remove shebangs and execute permission from non-script executables

These files’ filesystem permissions included the executable bit and they
had shebang lines, but they have no “main routines” or interesting side
effects.

qdarkstyle/__init__.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 """The most complete dark/light style sheet for Qt applications (Qt4, Qt5,

qdarkstyle/utils/__init__.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 """
 Utilities for processing SASS and images from default and custom palette.

qdarkstyle/utils/images.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 """
 Utilities to process and convert svg images to png using palette colors.