Move Simple.h and Alias.h to include/Core.

Because the files in Core actually depend on these files.

Differential Revision: http://reviews.llvm.org/D4000

llvm-svn: 210710
diff --git a/lld/lib/ReaderWriter/CoreLinkingContext.cpp b/lld/lib/ReaderWriter/CoreLinkingContext.cpp
index ff8fe37..0adaa01 100644
--- a/lld/lib/ReaderWriter/CoreLinkingContext.cpp
+++ b/lld/lib/ReaderWriter/CoreLinkingContext.cpp
@@ -11,9 +11,9 @@
 
 #include "lld/Core/Pass.h"
 #include "lld/Core/PassManager.h"
+#include "lld/Core/Simple.h"
 #include "lld/Passes/LayoutPass.h"
 #include "lld/Passes/RoundTripYAMLPass.h"
-#include "lld/ReaderWriter/Simple.h"
 
 #include "llvm/ADT/ArrayRef.h"