Rego functions for cache write and read (set and get)
I've put the cache functions in a more generic regofunc package so that we can
retrieve them from one place.
With the previous design where cache functions were placed in the CacheExt
struct it had a nice separation of concerns, but IMO it would make it more
difficult when we create new built-in functions, because we would have to create
multiple objects to retrieve the different functions. Please share your thoughts
on this if you have objections.
Closes #17 (closed)
Edited by Lyuben Penkovski