* Reorg of distributed backend access
details:
Now handled via API provided in `aristo_desc`.
* Rename `checkCache()` => `checkTop()`
why:
Better naming for top layer cache checker
also:
Provide cascaded fifos checker
* Provide `eq` directive for finding filter by exact filter ID (think block number)
* Some code beautification (for better code reading)
* State root reposition and reorg
details:
Repositioning is supported by forking a new descriptor. Reorg is then
accomplished by writing this forked state on the backend database.
Jordan Hrycaj