Ensure a kitty executable is on PATH even when running from source

launcher/kitty

@@ -0,0 +1,13 @@
+#!/usr/bin/env python3
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
+
+import os
+import sys
+
+base = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+sys.path.insert(0, base)
+with open(os.path.join(base, '__main__.py')) as f:
+    src = f.read()
+code = compile(src, f.name, 'exec')
+exec(code, {'__name__': '__main__'})