Use more explicit include paths.

This helps clarify dependencies and simplifies include paths.

Bug swiftshader:86

Change-Id: I564ee420bb9029fa6428e49b63a86d633301bec2
Reviewed-on: https://swiftshader-review.googlesource.com/13288
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>

src/Shader/PixelShader.cpp

diff --git a/src/Shader/PixelShader.cpp b/src/Shader/PixelShader.cpp
index c659248..9e36be6 100644
--- a/src/Shader/PixelShader.cpp
+++ b/src/Shader/PixelShader.cpp
@@ -14,7 +14,7 @@
 
 #include "PixelShader.hpp"
 
-#include "Debug.hpp"
+#include "Common/Debug.hpp"
 
 #include <string.h>