[ci skip] Fix style guide typos
Give Drivers a higher priority in the autoloader
Loader changes & optimizations related to issue #2551
[ci skip] Alter the welcome page
Cache Driver - Backup Never Loaded
The condition that checks to see if the backup driver input is valid was prefixing the input with "cache_". Since the valid driver values don't have this prefix, the condition was always returning FALSE and the backup drivers were never being loaded.
I've removed the prefix in the condition and added a debug log message for when the backup driver is used.
Merge pull request #2555 from refringe/develop

Cache Driver - Backup Never Loaded
Fixes in JavaScript Library
Merge pull request #2556 from vlakoff/develop-4

Fixes in JavaScript Library
Fix #2558
Merge branch 'develop' of github.com:EllisLab/CodeIgniter into develop
fixed issue #2560

originally, the form_open() looks for an empty string to set the
'method=post' attribute on the form tag.

I changed this to accept empty arrays and arrays that don't have a
'method' key.

Issue #2560