Remove deprecated function
Hide some output
Move the app creation to a factory class

This also deprecates the use of storing the last appname in the session.
The only extra case is during the user's logout and it should be the
site, the one to decide where to redirect.
Also, prepares the code better for a future request params validation
Log the incoming request
Fix templates requiring access to the config
Get .htaccess generated in the build folder
Filter the plain URL
Un-ignore some files
Move some defaults and param checks

Move them out of the App class to the AppFactory.
AppFactory will be the one adjusting and checking the parameters
that the concrete App would be safe to use.

Also, we can start using $this->params in App as safe variables
Move the app,page,a validation to the AppFactory

Adds extra page and action validation by new config keys. Adjust the example site
config to reflect this.
Merge page and action variables

Until now, 'page' was meant for showing output in the default template and
'action' indicated what app's method to run (optional)

From now on, the 'page' param indicates the method to run. If it's not
found in the request, it's taken from the app's config variable 'init_page'.

The method now *is required to exists* in the app's class (and not be private).

The page that's used in the default template is, by default, that with the
same name than the contents of the 'page' param. It's stored in the variable
$app->page and so, can be changed in the method for different purpouses,
like redirection.
Fix example site for the latest changes
Fix for keys with more than 2 levels
Add page parameters validation support

It uses PHP's native filter functions (http://www.php.net/manual/en/book.filter.php)
and so, supports all the types listed there, including custom callback-based
validators.

The validators are specified in the config file on a per-param basis.
Each parameter can only have one validator assigned; if you need to apply more,
do it in a custom function with the callback validator type.

As an extra, you can also define required parameters.
Finished item
Add some examples of param validation

Three examples included: int, regexp and callback.
The latest needs a new 'my_validator' custom validation function defined
in the example_app class.
Check that params info is defined before using it