Add Plugin for UTXO tracking by account. (neo-project#65)

* Add Plugin for UTXO tracking by account.

* Rename RpcSystemAssetPlugin -> RpcSystemAssetTracker.

* Accept address or script hash.

* Remove unnecessary white space.

* Update project ref to Neo 2.10.1-CI00002.

* Ensure consistency in case of crash or kill.

* Fix setting lastPersistedBlock after each block is persisted.

* Performance optimization: Don't write block number for empty blocks.

* Optimize.

* Add support for tracking unclaimed spent outputs.

* Provide getclaimable RPC call for getting available claim spent outputs.

* Clean-up.

* Don't leak memory.

* Implement getclaimable to get get total unclaimed amount for an address.

* Remove unnecessary comment.

* Fix size of UserSystemAssetCoinOutputs. Remove unused using statement.

* Reload max utxo's from configuration if it changes.

* Upgrade dependency

RpcSystemAssetTracker/RpcSystemAssetTracker.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <Version>2.10.1</Version>
+    <TargetFrameworks>netstandard2.0</TargetFrameworks>
+    <RootNamespace>Neo.Plugins</RootNamespace>
+    <LangVersion>latest</LangVersion>
+  </PropertyGroup>
+  <ItemGroup>
+    <None Update="RpcSystemAssetTracker\config.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
+    </None>
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Neo" Version="2.10.1" />
+  </ItemGroup>
+</Project>

RpcSystemAssetTracker/RpcSystemAssetTracker/config.json

@@ -0,0 +1,7 @@
+{
+  "PluginConfiguration": {
+    "DBPath": "SystemAssetBalanceData",
+    "MaxReturnedUnspents": 1000,
+    "TrackUnclaimed": true
+  }
+}