Adding theme_backup and default_template settings see #7328

Blocks added in templates in order to be overwrite.
Minor - format code.
Removing "periodo" code see:

https://github.com/chamilo/chamilo-lms/commit/a1bb6d404086a06489933797a6c23f0b03fc6c06#commitcomment-8173685
Adding script to check users.
Merge branch '1.9.x' of ssh://github.com/chamilo/chamilo-lms into chamilo19