Initial algorithm for nominating valid 'parallel' tx sets.

This is a relatively simple algorithm, but it should be serviceable for traffic with relatively low amount of transitive IO conflicts.

Author: dmkozh

Builds/VisualStudio/stellar-core.vcxproj

@@ -518,6 +518,7 @@ exit /b 0
     <ClCompile Include="..\..\src\herder\HerderSCPDriver.cpp" />
     <ClCompile Include="..\..\src\herder\HerderUtils.cpp" />
     <ClCompile Include="..\..\src\herder\LedgerCloseData.cpp" />
+    <ClCompile Include="..\..\src\herder\ParallelTxSetBuilder.cpp" />
     <ClCompile Include="..\..\src\herder\PendingEnvelopes.cpp" />
     <ClCompile Include="..\..\src\herder\QuorumIntersectionCheckerImpl.cpp" />
     <ClCompile Include="..\..\src\herder\QuorumTracker.cpp" />
@@ -972,6 +973,7 @@ exit /b 0
     <ClInclude Include="..\..\src\herder\HerderSCPDriver.h" />
     <ClInclude Include="..\..\src\herder\HerderUtils.h" />
     <ClInclude Include="..\..\src\herder\LedgerCloseData.h" />
+    <ClInclude Include="..\..\src\herder\ParallelTxSetBuilder.h" />
     <ClInclude Include="..\..\src\herder\PendingEnvelopes.h" />
     <ClInclude Include="..\..\src\herder\QuorumIntersectionChecker.h" />
     <ClInclude Include="..\..\src\herder\QuorumIntersectionCheckerImpl.h" />

Builds/VisualStudio/stellar-core.vcxproj.filters

@@ -1365,6 +1365,15 @@
     <ClCompile Include="..\..\src\catchup\LedgerApplyManagerImpl.cpp">
       <Filter>catchup</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\herder\ParallelTxSetBuilder.cpp">
+      <Filter>herder</Filter>
+    </ClCompile>
+    <ClCompile Include="..\..\src\simulation\ApplyLoad.cpp">
+      <Filter>simulation</Filter>
+    </ClCompile>
+    <ClCompile Include="..\..\src\simulation\TxGenerator.cpp">
+      <Filter>simulation</Filter>
+    </ClCompile>    
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\lib\util\cpptoml.h">
@@ -2360,6 +2369,15 @@
     <ClInclude Include="..\..\src\main\QueryServer.h">
       <Filter>main</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\src\herder\ParallelTxSetBuilder.h">
+      <Filter>herder</Filter>
+    </ClInclude>
+    <ClInclude Include="..\..\src\simulation\ApplyLoad.h">
+      <Filter>simulation</Filter>
+    </ClInclude>
+    <ClInclude Include="..\..\src\simulation\TxGenerator.h">
+      <Filter>simulation</Filter>
+    </ClInclude>
     <ClInclude Include="..\..\src\ledger\LedgerStateSnapshot.h">
       <Filter>ledger</Filter>
     </ClInclude>