Consistently use #!/usr/bin/env python

At Ksplice we used /usr/bin/python because we shipped dependencies as Debian /
Red Hat packages, which would be installed against the system Python.  We were
also very careful to use only Python 2.3 features so that even old system
Python would still work.

None of that is true at Humbug.  We expect users to install dependencies
themselves, so it's more likely that the Python in $PATH is correct.  On OS X
in particular, it's common to have five broken Python installs and there's no
expectation that /usr/bin/python is the right one.

The files which aren't marked executable are not interesting to run as scripts,
so we just remove the line there.  (In general it's common to have libraries
that can also be executed, to run test cases or whatever, but that's not the
case here.)

(imported from commit 437d4aee2c6e66601ad3334eefd50749cce2eca6)

api/bin/humbug-send

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 # humbug-send -- Sends a message to the specified recipients.
 

api/examples/get-public-streams

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 # Copyright © 2012 Humbug, Inc.

api/examples/list-members

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 # Copyright © 2013 Humbug, Inc.

api/examples/list-subscriptions

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 # Copyright © 2012 Humbug, Inc.

api/examples/print-messages

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 # Copyright © 2012 Humbug, Inc.

api/examples/print-next-message

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 # Copyright © 2012 Humbug, Inc.

api/examples/send-message

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 # Copyright © 2012 Humbug, Inc.

api/examples/subscribe

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 # Copyright © 2012 Humbug, Inc.

api/examples/unsubscribe

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 # Copyright © 2012 Humbug, Inc.

api/humbug/__init__.py

@@ -1,4 +1,3 @@
-#!/usr/bin/python
 # -*- coding: utf-8 -*-
 
 # Copyright © 2012 Humbug, Inc.

api/integrations/trac/humbug_trac.py

@@ -1,4 +1,3 @@
-#!/usr/bin/python
 # -*- coding: utf-8 -*-
 
 # Copyright © 2012 Humbug, Inc.

bots/check-mirroring

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 import sys
 import time
 import optparse

bots/feedback-bot

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 import sys
 from os import path
 import logging

bots/sync-public-streams

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 import sys
 from os import path
 import logging

bots/zephyr_mirror.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # Copyright (C) 2012 Humbug, Inc.
 #
 # Permission is hereby granted, free of charge, to any person

bots/zephyr_mirror_backend.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # Copyright (C) 2012 Humbug, Inc.
 #
 # Permission is hereby granted, free of charge, to any person

tools/inject-messages/inject-messages

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 import sys
 import os
 import optparse

tools/merge-messages-logs

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 import simplejson
 
 items_by_timestamp = {}

tools/post-receive

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 #
 # Humbug's post-receive hook.  There is a symlink
 #   from /srv/git/humbug.git/hooks/post-receive

tools/restart-server

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 import os
 import sys
 import subprocess

tools/update-deployment

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 import os
 import sys
 import subprocess

zephyr/lib/bugdown/codehilite.py

@@ -1,5 +1,3 @@
-#!/usr/bin/python
-
 """
 CodeHilite Extension for Python-Markdown
 ========================================