Updated third party code to latest version

- updated jQuery from 1.8.2 to v1.9.1
- updated Colorbox from 1.3.20.1 to v1.4.14
Some updates for the SilverStripe 3.0.x branch
Moved some settings from _config.php to _config/settings.yml
Update README.md
Update README.md
Added option to sort images by EXIF creation date

- can be activated via _config/settings.yml IMAGE_SORT_OPTION: 4
- thanks to Joop53 for the idea
Removed unsupported setting from 3.0.x branch
Updated comment blocks
Fixed typo in variable name
Updated 3rd party packages to latest version

- updated jQuery to v1.10.1
- updated jQuery Colorbox to v1.4.18
Fixed possible timeout issues when updating EXIF dates

- limited EXIF database updates to image objects assigned to page saved
- fix possible timeout issues when dealing with lots of image objects
Changed hook to update EXIF dates after write

- changed hook from onBeforeWrite to onAfterWrite
- suppressed possible warnings in exif_read_data function
Updated 3rd party packages

- updated jQuery to v1.10.2
- updated jQuery Colorbox to v1.4.26