Miscellaneous ExtEventLoop stuff.

* Added `ExtEventLoop` to the event-loop readme file
* Added `ext-event` to composer suggestions
* Added messages to composer suggestions (suggest doesn't use version constraints)

Author: jmalloc

composer.json

@@ -27,9 +27,9 @@
         "react/dns": "self.version"
     },
     "suggest": {
-        "ext-libevent": "*",
-        "ext-event": "*",
-        "ext-libev": "*"
+        "ext-libevent": "Allows for use of a more performant event-loop implementation.",
+        "ext-libev": "Allows for use of a more performant event-loop implementation.",
+        "ext-event": "Allows for use of a more performant event-loop implementation."
     },
     "autoload": {
         "psr-4": {

composer.lock

@@ -20,11 +20,15 @@ In addition to the interface there are some implementations provided:
   ([github](https://github.com/m4rw3r/php-libev)). It supports the same
   backends as libevent.
 
+* `ExtEventLoop`: This uses the `event` pecl extension. It supports the same
+  backends as libevent.
+
 All of the loops support these features:
 
 * File descriptor polling
 * One-off timers
 * Periodic timers
+* Deferred execution of callbacks
 
 ## Usage