Initial commit
Added UserBlockIds to Superblock
[StellaDB] Transaction
[StellaDB] Pager to optimize I/O performance
[StellaDB] Opening Database
[StellaDB] STON (Stella Object Notation) Serialization
[StellaDB] Made DeleteOnCloseFileStream sealed
[StellaDB/Ston] fixed deserialization issue

Now can deserialize STON to non-<string, object>/<object> collections when no converters are given
[StellaDB/Ston] Fixed stringified integer serializaton
[StellaDBBenchmark] Added STON Benchmark
[StellaDB] StonReader/StonWriter
[StellaDBBenchmark] Add StonReader Benchmark
[StellaDB] QueryOptimizer/Index (incomplete)
[StellaDB] IndexConverter
[StellaDB] SerializedStonVariant
[StellaDB] Now all key parameters derive from KeyParameter