Adding Cloudflare integration

This commit introduces upstream integration with Cloudflare. This
allows a user that also uses Cloudflare to directly publish their
blacklist entries with Cloudflare, which will help shed traffic
upstream in the event of an attack.
Include upstream.h in repsheet.c
Don't make the Cloudflare call if the credentials can't be found.
Let pkg-config deal with resolving libraries instead of hardcoding
Looks like hiredis is more complicated across OSes. Pulling from .ac for now
Fall back to jsonc 0.9 as the minimum version
Lower the required version of libcurl to 7.14+
Reduce the number of calls to Redis during score()
Cleanup in upstream.c
Update usage printer
Version bump
Merge branch 'master' into debian