Don't enabled the language_selection_page page in hook_menu if the block method is enabled.

- Admin page:
  - New setting to select the path of the language selection page.
  - Display warnings when the configuration is not setup correctly, based on the install requirements.

- Module:
 - The negotiation is faster thanks to a series of check who detects if the language can be determined or not.
 - It's easier to read and understand for everyone.
 - Removed the call to locale_language_from_url().
 - Added more documentation

 Important: if you choose the 'Template in theme' or 'In a drupal block' method, Drupal will automatically set the language to the default one because to display these, it needs to display a page, and as none of the negotiation responded, it will automatically assign the default one, but the Language Selection Page (page or block) will be displayed only once.

Redirect properly the user if it still land on the 'language_selection' page when enabling the block system.

Provide the $language_selection_page data variable in that block too.

Replace every $_GET['q'] with request_path().
Adding more checks to be sure that the language is not found through the different negociation subsystems.

Blacklisted paths are now automatically set when installing the module.
Remove ununsed variables to delete when uninstalling.
/!\ Changed the name of the template for more consistency.
/!\ Changed the way links are built in the template so there's no more hardcoded text, the links are built in the template directly.

/!\ Be aware that this release WILL break your current setup. /!\

Now that we are relying on 'html' default Drupal's template, we can remove the useless one and do a cleanup.

git authored Feb 05, 2013 and Pol Dellaiera committed Feb 05, 2013

Fix #1908510: Unable to call update.php when the module is enabled and language is not stored in cookie.