Survival waves

[tkstanczak]

For review:

• MemCountingCache (check if tested, check if needed)
• NUNitLogManagerand NUnitLogger
• TrieNodeChae, TrieStore, TrieNode, PatriciaTriee changes for pruning
• IPruningStrategy, ISnapshotStrategy
• important resettable fix (adding missing comparer)
• addition of logging to PatriciaTrie and nodes

Remaining items:

• cleaning the TrieStore / TrieCache relationship
• cleaning the PruningStrategy and SnapshotStrategy rules
• cleaning the propagation of TrieStore
• fixing tests
• adding tests for the two replace-storage cases
• adding test cases for the short RLP
• reacting to memory growth in the cache
• support for reorgs (already there, needs connecting and testing)