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

libc/bits/roundup2pow.c

@@ -26,5 +26,5 @@
  * @see rounddown2pow()
  */
 unsigned long roundup2pow(unsigned long x) {
-  return x > 1 ? 1ul << (bsrl(x - 1) + 1) : x ? 1 : 0;
+  return x > 1 ? 2ul << bsrl(x - 1) : x ? 1 : 0;
 }