Exec with real path to python wrappers

Makes it possible to symlink to them from /usr/bin etc
to make dist packaging easier.

Could probably be done with shell script but python is already
requried so it seems more portable.

Add missing exec bit for mp4-hls.py

Source/Python/wrappers/mp4dash

@@ -1,3 +1,3 @@
-#! /bin/bash
-BASEDIR=$(dirname $0)
-exec python "$BASEDIR/../utils/mp4-dash.py" "$@"
+#!/usr/bin/env python
+import os,sys
+os.execv(os.path.dirname(os.path.realpath(sys.argv[0])) + "/../utils/mp4-dash.py", sys.argv)

Source/Python/wrappers/mp4dashclone

@@ -1,3 +1,3 @@
-#! /bin/bash
-BASEDIR=$(dirname $0)
-exec python "$BASEDIR/../utils/mp4-dash-clone.py" "$@"
+#!/usr/bin/env python
+import os,sys
+os.execv(os.path.dirname(os.path.realpath(sys.argv[0])) + "/../utils/mp4-dash-clone.py", sys.argv)

Source/Python/wrappers/mp4hls

@@ -1,3 +1,3 @@
-#! /bin/bash
-BASEDIR=$(dirname $0)
-exec python "$BASEDIR/../utils/mp4-hls.py" "$@"
+#!/usr/bin/env python
+import os,sys
+os.execv(os.path.dirname(os.path.realpath(sys.argv[0])) + "/../utils/mp4-hls.py", sys.argv)