Fix missing dates in templates
Remove get_exif_data_from_path - we can always get a file easily
Speed up tests with django-inmemorystorage

There's a few places we can't use it for some reason,
hopefully I'll figure those out and can remove the settings
override.
Be more consistent about how we call is_valid_image
p is a terrible variable name
Update README with next steps
If we fail to read EXIF data, reset the file pointer