Merge remote-tracking branch 'upstream/master'
Update dalli settings for larger items
Handle problematic EXIF data
Update metadata spec to cover nil keys
Merge pull request #204 from robotmay/master

Bugfixes for image processing issues
Update queue system to reduce memory consumption
Security update for rails
Sort categories in nav by localised name
Merge pull request #207 from robotmay/master

Security and performance updates
Merge pull request #208 from robotmay/category-order

Sort the categories in the nav by their localised names
Merge remote-tracking branch 'upstream/master'
Add next/previous arrows for flicking through collections
Remove debug code
Fix failing specs
Merge pull request #209 from robotmay/next-prev-arrows

Add next/previous arrows for flicking through collections
Update README.md