Restructing the source layout to make it nicer.

meson.build

@@ -25,6 +25,8 @@ dependencies = [
   sfml, imgui, json
 ]
 
+subdir('scratchpad')
+
 executable('escape_turings_tarpit',
   ['game_engine.cpp',
     'gui.cpp',
@@ -34,30 +36,6 @@ executable('escape_turings_tarpit',
     'escape_turings_tarpit.cpp'],
   dependencies: dependencies)
 
-executable('regtest', 'regtest.cpp',
-  dependencies: [fmt])
-
-executable('audiotest', 'audiotest.cpp',
-  dependencies: dependencies)
-
-executable('jsontest', 'jsontest.cpp',
-  dependencies: dependencies)
-
-executable('threadtest', 'threadtest.cpp',
-  dependencies: dependencies)
-
-executable('fsmtest', 'fsmtest.cpp',
-  dependencies: dependencies)
-
-executable('badref', 'badref.cpp',
-  dependencies: dependencies)
-
-executable('corotest', [
-    'corotest.cpp'
-  ],
-  dependencies: dependencies,
-  cpp_args: '-fcoroutines')
-
 runtests = executable('runtests', [
   'game_engine.cpp',
   'tests/game_engine.cpp',