Added better header parsing to Request-class.

- Added `tryParse` argument to the `getHeader` method. When enabled the method will try to parse headers from both server and client-side (enabled by default).
- Simplified references that checks for both variants of header (http/non http).
- Simplified getIp method of the Request-class.

src/Pecee/SimpleRouter/SimpleRouter.php

@@ -466,7 +466,7 @@ class SimpleRouter
     /**
      * Get the request
      *
-     * @return \Pecee\Http\Request
+     * @return Request
      */
     public static function request(): Request
     {