Clean up scr/ directory

* remove scr/abjad-log
* remove scr/fix-tests
* remove scr/make-packaging-transcript
* remove scr/trash

OLD: scr/abjad
NEW: scr/abjad.py

OLD: scr/prime-parser-tables
NEW: scr/prime_parser_tables.py

OLD: scr/timer
NEW: scr/timer.py

OLD: scr/write-parser-syntax-skeleton
NEW: scr/write_parser_syntax_skeleton.py

abjad/contextmanagers.py

@@ -703,7 +703,7 @@ def __enter__(self) -> "Timer":
         self._stop_time = None
         self._start_time = time.time()
         if self.print_continuously_from_background:
-            path = configuration.abjad_directory.parent / "scr" / "timer"
+            path = configuration.abjad_directory.parent / "scr" / "timer.py"
             interval = str(int(self.print_continuously_from_background))
             process = subprocess.Popen([path, interval], shell=False)
             self._process = process

scr/abjad → scr/abjad.py

@@ -1,5 +1,4 @@
 #! /usr/bin/env python
-import pathlib
 import sys
 
 import abjad

scr/timer → scr/timer.py

@@ -1,4 +1,9 @@
 #! /usr/bin/env python
+
+"""
+Called by abjad.contextmanager.Timer on __enter__().
+"""
+
 import sys
 import time
 

scr/write-parser-syntax-skeleton → scr/write_parser_syntax_skeleton.py

@@ -11,7 +11,7 @@ def usage():
     result.append("Usage:")
     result.append("")
     result.append(
-        "write-parser-syntax-skeleton PARSER_output_PATH PARSER_TAB_HH_PATH SKELETON_PATH"
+        "write_parser_syntax_skeleton.py PARSER_output_PATH PARSER_TAB_HH_PATH SKELETON_PATH"
     )
     result.append("")
     result.append(
@@ -29,7 +29,9 @@ def write(parser_output_path, parser_tab_hh_path, skeleton_path):
     assert os.path.exists(parser_output_path)
     assert os.path.exists(parser_tab_hh_path)
     LilyPondGrammarGenerator()._write_parser_syntax_skeleton(
-        skeleton_path, parser_output_path, parser_tab_hh_path,
+        skeleton_path,
+        parser_output_path,
+        parser_tab_hh_path,
     )