Changed code indents from tabs to spaces

Author: C-Stevens

doc/classes.md

@@ -5,20 +5,18 @@
 #### PHP
 ```php
 <?php
-	class myClass {
-    	public $foo = 1
-        
+    class myClass {
+        public $foo = 1
         public function returnFoo() {
-        	echo $this->foo;
+            echo $this->foo;
         }
     }
 ?>
 ```
 #### Python
 ```python
 class myClass:
-    foo = 1
-    
+    foo = 1   
 	def returnFoo(self):
     	return self.foo