[phpdoc] Add API documentation.

This is a starting point to add a documentation of the whole set of APIs and
classes of Predis. The next step will be to actually improve and extend it.

lib/Predis/ClientOptions.php

@@ -17,6 +17,11 @@ use Predis\Options\ClientProfile;
 use Predis\Options\ClientCluster;
 use Predis\Options\ClientConnectionFactory;
 
+/**
+ * Class that manages validation and conversion of client options.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
 class ClientOptions
 {
     private static $_sharedOptions;
@@ -26,12 +31,20 @@ class ClientOptions
 
     private $_options = array();
 
+    /**
+     * @param array $options Array of client options.
+     */
     public function __construct(Array $options = array())
     {
         $this->_handlers = $this->initialize($options);
         $this->_defined = array_keys($options);
     }
 
+    /**
+     * Ensures that the default options are initialized.
+     *
+     * @return array
+     */
     private static function getSharedOptions()
     {
         if (isset(self::$_sharedOptions)) {
@@ -48,18 +61,35 @@ class ClientOptions
         return self::$_sharedOptions;
     }
 
+    /**
+     * Defines an option handler or overrides an existing one.
+     *
+     * @param string $option Name of the option.
+     * @param IOption $handler Handler for the option.
+     */
     public static function define($option, IOption $handler)
     {
         self::getSharedOptions();
         self::$_sharedOptions[$option] = $handler;
     }
 
+    /**
+     * Undefines the handler for the specified option.
+     *
+     * @param string $option Name of the option.
+     */
     public static function undefine($option)
     {
         self::getSharedOptions();
         unset(self::$_sharedOptions[$option]);
     }
 
+    /**
+     * Initializes client options handlers.
+     *
+     * @param array $options List of client options values.
+     * @return array
+     */
     private function initialize($options)
     {
         $handlers = self::getSharedOptions();
@@ -76,11 +106,23 @@ class ClientOptions
         return $handlers;
     }
 
+    /**
+     * Checks if the specified option is set.
+     *
+     * @param string $option Name of the option.
+     * @return Boolean
+     */
     public function __isset($option)
     {
         return in_array($option, $this->_defined);
     }
 
+    /**
+     * Returns the value of the specified option.
+     *
+     * @param string $option Name of the option.
+     * @return mixed
+     */
     public function __get($option)
     {
         if (isset($this->_options[$option])) {