Move scripts to /src subdirectory

src/MD_STD_IN.php

@@ -5,8 +5,7 @@
 declare(strict_types = 1);
 
 /**
- * Standard class providing overrides of default PHP functions as static
- * functions.
+ * Encapsulates functions for handling inputs.
  */
 final class MD_STD_IN {
     /**

src/MD_STD_SEC.php

@@ -5,7 +5,7 @@
 declare(strict_types = 1);
 
 /**
- * Class providing static functions with basic security operations.
+ * Gathers wrappers for handling basic security operations.
  */
 final class MD_STD_SEC {
     /**