Added cloudflare cache invalidation
Improved multi backend support in wagtailfrontendcache
WAGTAILFRONTENDCACHE_LOCATION compatibility
Readded purge_url_from_cache. Logging improvements
Docs for cloudflare cache invalidation
Merge remote-tracking branch 'torchbox/master' into cloudflare-cache-invalidation
Fixed broken tests
Frontendcache backend logging changes
Merge pull request #505 from kaedroho/cloudflare-cache-invalidation

Added cloudflare cache invalidation