Add a defensive check in CI_Loader::_ci_load()

Prevents possible internal variable overwrites when loading views
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 52e8d13..11d7918 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -10,6 +10,7 @@
 -  Core
 
    -  Changed :doc:`Loader Library <libraries/loader>` to allow ``$autoload['drivers']`` assigning with custom property names.
+   -  Changed :doc:`Loader Library <libraries/loader>` to ignore variables prefixed with '_ci_' when loading views.
 
 -  General Changes