Get rid of the various different launchers

Now there is only one launcher. Which means it can be used to start
kitty with profiling and ASAN in the natural way. The recommended
way to run kitty from source is now:

./kitty/launcher/kitty

The launcher also automatically re-execs to resolve symlinks on macOS.

kitty/main.py

@@ -4,9 +4,9 @@
 
 import locale
 import os
+import shutil
 import sys
-from contextlib import contextmanager
-from contextlib import suppress
+from contextlib import contextmanager, suppress
 
 from .borders import load_borders_program
 from .boss import Boss
@@ -174,7 +174,7 @@ def setup_profiling(args):
     if stop_profiler is not None:
         import subprocess
         stop_profiler()
-        exe = os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), 'kitty-profile')
+        exe = kitty_exe()
         cg = '/tmp/kitty-profile.callgrind'
         print('Post processing profile data for', exe, '...')
         subprocess.call(['pprof', '--callgrind', exe, '/tmp/kitty-profile.log'], stdout=open(cg, 'wb'))
@@ -225,11 +225,14 @@ def _main():
         except Exception:
             log_error('Failed to set locale with no LANG, ignoring')
 
-    # Ensure kitty is in PATH
-    rpath = os.path.dirname(kitty_exe())
-    items = frozenset(os.environ['PATH'].split(os.pathsep))
-    if rpath and rpath not in items:
-        os.environ['PATH'] = rpath + os.pathsep + os.environ.get('PATH', '')
+    # Ensure the correct kitty is in PATH
+    rpath = sys._xoptions.get('bundle_exe_dir')
+    if rpath:
+        modify_path = is_macos or getattr(sys, 'frozen', False) or sys._xoptions.get('kitty_from_source') == '1'
+        if modify_path or not shutil.which('kitty'):
+            existing_paths = list(filter(None, os.environ.get('PATH', '').split(os.pathsep)))
+            existing_paths.insert(0, rpath)
+            os.environ['PATH'] = os.pathsep.join(existing_paths)
 
     args = sys.argv[1:]
     if is_macos and os.environ.pop('KITTY_LAUNCHED_BY_LAUNCH_SERVICES', None) == '1':