New unit_test framework:

* Header-only!
* No external dependencies or other beast modules
* Compilation options allow for:
  - Stand-alone application to run a single test suite
  - Stand-alone application to run a set of test suites
  - Global suite of tests inline with the host application
  - Disable test suite generation completely
* Existing tests reworked to use the new classes

beast/net/impl/DynamicBuffer.cpp

@@ -17,10 +17,15 @@
 */
 //==============================================================================
 
-#include <memory>
+#if BEAST_INCLUDE_BEASTCONFIG
+#include "../../BeastConfig.h"
+#endif
 
 #include "../DynamicBuffer.h"
 
+#include <algorithm>
+#include <memory>
+
 namespace beast {
 
 DynamicBuffer::DynamicBuffer (size_type blocksize)