Change to the treatment of BeastConfig.h

* No longer requires its own compiler include path
* Includes use relative paths to locate the file
* Client applications include the file themselves
* Inclusion of BeastConfig.h can be controlled via preprocessor directive

beast/http/impl/joyent_parser.cpp

@@ -17,10 +17,6 @@
 */
 //==============================================================================
 
-#include "BeastConfig.h"
-
-#include "../../Config.h"
-
 namespace beast {
 namespace joyent {