Sort all of Clang's files under 'lib', and fix up the broken headers
uncovered.

This required manually correcting all of the incorrect main-module
headers I could find, and running the new llvm/utils/sort_includes.py
script over the files.

I also manually added quite a few missing headers that were uncovered by
shuffling the order or moving headers up to be main-module-headers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169237 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index 6cd1846..ab30049 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -25,12 +25,12 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Lex/Lexer.h"
-#include "clang/Lex/Preprocessor.h"
-#include "clang/Lex/LexDiagnostic.h"
-#include "clang/Lex/CodeCompletionHandler.h"
 #include "clang/Basic/SourceManager.h"
-#include "llvm/ADT/StringSwitch.h"
+#include "clang/Lex/CodeCompletionHandler.h"
+#include "clang/Lex/LexDiagnostic.h"
+#include "clang/Lex/Preprocessor.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include <cstring>