Revert the shebang stuff

Per personal request in discussion of PR #306[1].

[1]: https://github.com/falkTX/Cadence/pull/306#issuecomment-775951549

src/canvaspreviewframe.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # Custom Mini Canvas Preview, a custom Qt widget

src/claudia_database.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # Package database

src/clickablelabel.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # Clickable Label, a custom Qt widget

src/jacklib.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # JACK ctypes definitions for usage in python applications

src/jacklib_helpers.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # Helper functions for extra jacklib functionality

src/patchcanvas.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # PatchBay Canvas engine using QGraphicsView/Scene

src/patchcanvas_theme.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # PatchBay Canvas Themes

src/shared.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # Common/Shared code

src/shared_cadence.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # Common/Shared code for Cadence

src/shared_canvasjack.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # Common/Shared code related to Canvas and JACK

src/shared_settings.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
 # Common/Shared code related to the Settings dialog