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

test/libc/fmt/atoi_test.c

@@ -337,6 +337,7 @@ TEST(strtoumax, testZero) {
 }
 TEST(strtoumax, testDecimal) {
   EXPECT_EQ(123, strtoumax("123", NULL, 0));
+  EXPECT_EQ(-123, strtoumax("-123", NULL, 0));
 }
 TEST(strtoumax, testHex) {
   EXPECT_EQ(255, strtoumax("0xff", NULL, 0));