Store third-party in separate directory (#812)

examples/rest_description.cc

@@ -8,7 +8,7 @@
 #include <pistache/description.h>
 #include <pistache/endpoint.h>
 
-#include <pistache/serializer/rapidjson.h>
+#include <pistache/thirdparty/serializer/rapidjson.h>
 
 using namespace std;
 using namespace Pistache;

src/common/http_defs.cc

@@ -12,7 +12,7 @@
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wconversion"
 #endif
-#include <pistache/date.h>
+#include <pistache/thirdparty/date.h>
 #ifdef __GNUC__
 #pragma GCC diagnostic pop
 #endif

tests/cookie_test.cc

 #include "gtest/gtest.h"
 
 #include <pistache/cookie.h>
-#include <pistache/date.h>
+#include <pistache/thirdparty/date.h>
 
 using namespace Pistache;
 using namespace Pistache::Http;

tests/cookie_test_2.cc

 #include "gtest/gtest.h"
 
 #include <pistache/cookie.h>
-#include <pistache/date.h>
+#include <pistache/thirdparty/date.h>
 
 using namespace Pistache;
 using namespace Pistache::Http;

tests/headers_test.cc

-#include <pistache/date.h>
 #include <pistache/http.h>
+#include <pistache/thirdparty/date.h>
 
 #include "gtest/gtest.h"