Make fixes, improvements, and chibicc python bindings

- python now mixes audio 10x faster
- python octal notation is restored
- chibicc now builds code 3x faster
- chibicc now has help documentation
- chibicc can now generate basic python bindings
- linenoise now supports some paredit-like features

See #141

third_party/dlmalloc/dlmalloc_stats.c

@@ -22,7 +22,7 @@
  */
 struct MallocStats dlmalloc_stats(mstate m) {
   struct MallocStats res;
-  memset(&res, 0, sizeof(res));
+  bzero(&res, sizeof(res));
   ensure_initialization();
   if (!PREACTION(m)) {
     check_malloc_state(m);