this is not going to be backwards compatible change, but it will be the first tagged libknot release sufficient for resolver

interface split to ‘map’ and ‘set’
added documentation
array: added array_tail() operation

- cache is now fully optional, resolution works without cache as well
- proper mempool per each request, not mixed
- zone cut resolution doesn't need any per-context memory
- now it's possible to do qname minimization
- rplan keeps tabs on resolved queries
- added documentation etc.