Changed directory structure to support Sparks package management.

The directory structure was changed around in preparation to support
the Sparks package management system for CodeIgniter (http://getsparks.org).

The following things took place in this commit:
1. Move all contents of the application/ directory up one level.
 * config/ controllers/ helpers/ language/ libraries/ models/ views/
 * Left captcha/ alone... Not quite sure where to put it yet.
 * Delete the now-empty application/ directory
2. Create vendor/ folder and move phpass into it.
 * (phpass is now in vendor/phpass-0.3/)
3. Change libraries/Tank_auth.php to reflect the new path of the phpass library
4. Add spark.info
 * Spark package management system requires this to work properly