Changes to support CodeIgniter (Reactor) 2.0

Environment support eliminates the need to ignore database.php.  Instead, ignore the entire development dir.
Logs and cache are now in application folder instead of system.

CodeIgniter.gitignore

-*/config/database.php
-*/system/logs/log-*.php
-*/system/cache/*
-*/system/cache/!index.html
+*/config/development
+*/logs/log-*.php
+*/logs/!index.html
+*/cache/*
+*/cache/!index.html