Isolate the visible part of an application inside a public folder.

index.php and install.php are specialized for bootstrapping the
application.

This is essential when you have to hide files like composer.json or
phinx.yml containing sensitive information.
Moved the sample example.htaccess file to public.

Removed the rule protecting application, modules and system folders as
it's not protecting them anymore.
Merge pull request #58 from arteymix/3.4/feature/public-folder

Isolate the visible part of an application inside a public folder.