message: Remove Event::wait from README
diff: @@ -32,6 +32,7 @@ Concurrency 10K requests to read data from MySQL takes only 0.2s!
  ```php
  $s = microtime(true);
  +Co\run(function() {
  for ($c = 100; $c--;) {
  go(function () {
  $mysql = new Swoole\Coroutine\MySQL;
  @@ -48,7 +49,7 @@ for ($c = 100; $c--;) {
  }
  });
  }
  -Swoole\Event::wait();
  +});
  echo 'use ' . (microtime(true) - $s) . ' s';
  ```
  @@ -271,6 +272,7 @@ Simply call the `Swoole\Runtime::enableCoroutine()` method at the top of your sc
  ```php
  Swoole\Runtime::enableCoroutine();
  $s = microtime(true);
  +Co\run(function() {
  for ($c = 100; $c--;) {
  go(function () {
  ($redis = new Redis)->connect('127.0.0.1', 6379);
  @@ -279,7 +281,7 @@ for ($c = 100; $c--;) {
  }
  });
  }
  -Swoole\Event::wait();
  +});
  echo 'use ' . (microtime(true) - $s) . ' s';
  ```
  @@ -294,7 +296,7 @@ Just see what the Swoole brings, just imagine...
  ```php
  Swoole\Runtime::enableCoroutine();
  $s = microtime(true);
  -
  +Co\run(function() {
  // i just want to sleep...
  for ($c = 100; $c--;) {
  go(function () {
  @@ -426,8 +428,7 @@ for ($c = 128; $c--;) {
  }
  });
  }
  -
  -Swoole\Event::wait();
  +});
  echo 'use ' . (microtime(true) - $s) . ' s';
  ```
  