Implement transport of single string data.

In most cases only one string is sent per message and no pointer
tracking is needed.

This is only plumbing work, no changes to messages have been made yet.

common/TracyQueue.hpp

@@ -83,6 +83,7 @@ enum class QueueType : uint8_t
     ParamSetup,
     ParamPingback,
     CpuTopology,
+    SingleStringData,
     StringData,
     ThreadName,
     CustomStringData,
@@ -613,6 +614,7 @@ static constexpr size_t QueueDataSize[] = {
     sizeof( QueueHeader ) + sizeof( QueueParamSetup ),
     sizeof( QueueHeader ),                                  // param pingback
     sizeof( QueueHeader ) + sizeof( QueueCpuTopology ),
+    sizeof( QueueHeader ),                                  // single string data
     // keep all QueueStringTransfer below
     sizeof( QueueHeader ) + sizeof( QueueStringTransfer ),  // string data
     sizeof( QueueHeader ) + sizeof( QueueStringTransfer ),  // thread name