Update ctrl users/_admin/logout to not load unnecessary helpers
Add basic logout controller for registered users
Update routes for 'login', 'logout', and 'registration' to nicer regex-format
Finally delete incorrectly named migration files
Add migration 018_Add_user_codes_table
Clear folder assets/ from old admin assets
Add index.html to assets/
Merge branch 'develop' into feature/users
Update ICF_Model::_prep_input(). Closes #21

Updated method to be 100 times faster. Yay!
Merge branch 'develop' into feature/app-cores
Update ICF_Model: Fix wrong identifier of $fields in _prep_input()
Add an empty MY_Model at the bottom of ICF_Model
Add .htaccess
Merge branch 'develop' into feature/users
Add module 'docs' to display docs from markdown files
Add source folder of markdown files for docs
Update lib markdown

* Extract config to config file 'markdown.php'
* Add support for "prettyprint linenums" to fenced code blocks
Add scripts and styles for Google's prettify
Update ctlr docs/docs to set needed assets
Update login forms and lib users/Auth

* One form for login and admin/login used
* Re-confirm login on admin/login if user logged in, otherwise presents default login-form