Fix doc comments and remove unneeded usings

src/UuidInterface.php

@@ -5,46 +5,106 @@ namespace Rhumsaa\Uuid;
 interface UuidInterface
 {
 
+    /**
+     * @return integer
+     */
     public function compareTo(UuidInterface $other);
 
+    /**
+     * @return boolean
+     */
     public function equals($other);
 
+    /**
+     * @return BigNumberConverter
+     */
     public function getConverter();
 
+    /**
+     * @return string
+     */
     public function getHex();
 
     public function getFieldsHex();
 
+    /**
+     * @return string
+     */
     public function getClockSeqHiAndReservedHex();
 
+    /**
+     * @return string
+     */
     public function getClockSeqLowHex();
 
+    /**
+     * @return string
+     */
     public function getClockSequenceHex();
 
+    /**
+     * @return \DateTime
+     */
     public function getDateTime();
 
+    /**
+     * @return \Moontoast\Math\BigNumber
+     */
     public function getInteger();
 
+    /**
+     * @return string
+     */
     public function getLeastSignificantBitsHex();
 
+    /**
+     * @return string
+     */
     public function getMostSignificantBitsHex();
 
+    /**
+     * @return string
+     */
     public function getNodeHex();
 
+    /**
+     * @return string
+     */
     public function getTimeHiAndVersionHex();
 
+    /**
+     * @return string
+     */
     public function getTimeLowHex();
 
+    /**
+     * @return string
+     */
     public function getTimeMidHex();
 
+    /**
+     * @return string
+     */
     public function getTimestampHex();
 
+    /**
+     * @return string
+     */
     public function getUrn();
 
+    /**
+     * @return integer
+     */
     public function getVariant();
 
+    /**
+     * @return integer|null
+     */
     public function getVersion();
 
+    /**
+     * @return string
+     */
     public function toString();
 
 }