[C++] Revert use of auto in lambdas. Issue aeron-io#903.

Author: mjpt777

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/cpp/CppGenerator.java

@@ -2642,19 +2642,20 @@ private CharSequence appendDisplay(
  new Formatter(sb).format(
  indent + "{\n" +
  indent + " bool atLeastOne = false;\n" +
- indent + " builder << R\"(\"%2$s\": [)\";\n" +
- indent + " writer.%1$s().forEach(\n" +
- indent + " [&](auto &&%1$s)\n" +
+ indent + " builder << R\"(\"%3$s\": [)\";\n" +
+ indent + " writer.%2$s().forEach(\n" +
+ indent + " [&](%1$s &%2$s)\n" +
  indent + " {\n" +
  indent + " if (atLeastOne)\n" +
  indent + " {\n" +
  indent + " builder << \", \";\n" +
  indent + " }\n" +
  indent + " atLeastOne = true;\n" +
- indent + " builder << %1$s;\n" +
+ indent + " builder << %2$s;\n" +
  indent + " });\n" +
  indent + " builder << ']';\n" +
  indent + "}\n\n",
+ formatClassName(groupToken.name()),
  formatPropertyName(groupToken.name()),
  groupToken.name());
 
@@ -3108,7 +3109,8 @@ private CharSequence generateMessageLength(final List<Token> groups, final List<
  }
 
  new Formatter(sbSkip).format(
- indent + " %1$s().forEach([](auto &&e){ e.skip(); });\n",
+ indent + " %2$s().forEach([](%1$s &e){ e.skip(); });\n",
+ formatClassName(groupToken.name()),
  formatPropertyName(groupToken.name()));
 
  i = endSignal;