Refactor file structure to not conflict with mysql

Now all includes live within boost
Corrected convention for .hpp and .ipp
Corrected convention for impl/detail
Now detail is split into auth/aux/protocol/network_algorithms

test/unit/error.cpp

@@ -6,7 +6,7 @@
  */
 
 #include <gtest/gtest.h>
-#include "mysql/error.hpp"
+#include "boost/mysql/error.hpp"
 
 using namespace testing;
 using mysql::Error;