the Redis backend supports UNIX, TCP and custom ports
no real transactions nor iteration, but it’s not needed at the moment
transactions keep replies in a freelist, which is purged on transaction
commit / abort

also some cleanup and version bump to Q2

this prepares cache/txn structures to hold API as well, so we can get
rid of the global api

this fixes a problem when module is unloaded at runtime
and active

memcached is a distributed caching system, it is a good fit
for building resolvers with shared and replicated cache

this hooks into query resolution and collects counters on answers, queries and iterator

this allows for continuation of a function in the background,
a good use case for this is loading of chunks of data or I/O