v0.21.3: Deep Tx parsing and other useful helpers

Transaction data can be parsed now (according to block.tlb) to obtain some "internal" fields from phases, like fees or success flag(s). See TransactionTests.cs for more details;

Improvements to existing classes:

• Boc: new ParseFromHex and TryParseFromHex (in addition to ...FromBase64);
• Slice: LoadAndParseDict, TryLoadAndParseDict and ParseDict now accept optional IEqualityComparer<TKey>;
• Slice: new SkipRef so you don't need to read it to temporary variable;
• Slice/Cell: new ParseDictRef, LoadAndParseDictRef and TryLoadAndParseDictRef to work with Cell-as-value dicts;
• AddressUtils: new TrySetBounceable to validate address string and convert it to required bounceable mode in one call;
• ITonClient: new SyncStateCurrentSeqno property return current (synced to) masterchain height;
• ITonClient: new Deinit method to "forget" LiteServer currently connected to, and initiate new connection on next InitIfNeeded - for example if you detect that current LiteServer is not synced;
• TonOptions: new ConfigPathLocalTestnet and ConfigPathLocalMainnet properties, so you can use locally saved config instead of downloading it every time;