Fixed missing use ($name) in reject calls (#110)

* Fixed missing use($name) in reject calls

Without use($name) it was not avaliable in lambda and causing fatal error when trying to removeButton or removeButtonFromStack

* Update Buttons.php

Missing spaces

* Update Buttons.php

* Update Buttons.php

Writing resulting array after reject into $this->buttons property

Author: morfin60

src/PanelTraits/Buttons.php

@@ -76,14 +76,14 @@ public function initButtons()
 
     public function removeButton($name)
     {
-        $this->buttons->reject(function ($button) {
+        $this->buttons = $this->buttons->reject(function ($button) use ($name) {
             return $button->name == $name;
         });
     }
 
     public function removeButtonFromStack($name, $stack)
     {
-        $this->buttons->reject(function ($button) {
+        $this->buttons = $this->buttons->reject(function ($button) use ($name, $stack) {
             return $button->name == $name && $button->stack == $stack;
         });
     }