Refactor exceptions

I removed unnecessary constructors and unnecessary inheritance

app/Exceptions/BadUrlException.php

@@ -1,6 +1,9 @@
 <?php
-class FreshRSS_BadUrl_Exception extends FreshRSS_Feed_Exception {
+
+class FreshRSS_BadUrl_Exception extends \Exception {
+
 	public function __construct($url) {
 		parent::__construct('`' . $url . '` is not a valid URL');
 	}
+
 }

app/Exceptions/ContextException.php

@@ -3,8 +3,6 @@
 /**
  * An exception raised when a context is invalid
  */
-class FreshRSS_Context_Exception extends Exception {
-	public function __construct($message) {
-		parent::__construct($message);
-	}
+class FreshRSS_Context_Exception extends \Exception {
+
 }

app/Exceptions/EntriesGetterException.php

@@ -1,7 +1,5 @@
 <?php
 
-class FreshRSS_EntriesGetter_Exception extends Exception {
-	public function __construct($message) {
-		parent::__construct($message);
-	}
+class FreshRSS_EntriesGetter_Exception extends \Exception {
+
 }

app/Exceptions/FeedException.php

@@ -1,6 +1,5 @@
 <?php
-class FreshRSS_Feed_Exception extends Exception {
-	public function __construct($message) {
-		parent::__construct($message);
-	}
+
+class FreshRSS_Feed_Exception extends \Exception {
+
 }