libdebuggerd: cleanup.

Move libdebuggerd headers into their own directory for namespacing,
move some includes to the top of their implementing files, delete some
dead code.

Test: mma, treehugger
Change-Id: Ie4c44e32e2ab3bc678092899d257fd4ed634aa34
diff --git a/debuggerd/libdebuggerd/utility.cpp b/debuggerd/libdebuggerd/utility.cpp
index 7f450e6..1b74652 100644
--- a/debuggerd/libdebuggerd/utility.cpp
+++ b/debuggerd/libdebuggerd/utility.cpp
@@ -16,7 +16,7 @@
 
 #define LOG_TAG "DEBUG"
 
-#include "utility.h"
+#include "libdebuggerd/utility.h"
 
 #include <errno.h>
 #include <signal.h>