Revert changes relative to lib/*.[ch] recent renaming

This reverts renaming and usage of lib/*.h header files done
28-12-2012, reverting 2 commits:

  f871de0... build: make use of 76 lib/*.h renamed files
  ffd8e12... build: rename 76 lib/*.h files

This also reverts removal of redundant include guard (redundant thanks
to changes in above commits) done 2-12-2013, reverting 1 commit:

  c087374... curl_setup.h: remove redundant include guard

This also reverts renaming and usage of lib/*.c source files done
3-12-2013, reverting 3 commits:

  13606bb... build: make use of 93 lib/*.c renamed files
  5b6e792... build: rename 93 lib/*.c files
  7d83dff... build: commit 13606bbfde follow-up 1

Start of related discussion thread:

  http://curl.haxx.se/mail/lib-2013-01/0012.html

Asking for confirmation on pushing this revertion commit:

  http://curl.haxx.se/mail/lib-2013-01/0048.html

Confirmation summary:

  http://curl.haxx.se/mail/lib-2013-01/0079.html

NOTICE: The list of 2 files that have been modified by other
intermixed commits, while renamed, and also by at least one
of the 6 commits this one reverts follows below. These 2 files
will exhibit a hole in history unless git's '--follow' option
is used when viewing logs.

  lib/curl_imap.h
  lib/curl_smtp.h

lib/curl_ntlm_msgs.c

@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -20,7 +20,7 @@
  *
  ***************************************************************************/
 
-#include "curl_setup.h"
+#include "setup.h"
 
 #ifdef USE_NTLM
 
@@ -33,21 +33,21 @@
 
 #define DEBUG_ME 0
 
-#include "curl_urldata.h"
-#include "curl_non_ascii.h"
-#include "curl_sendf.h"
+#include "urldata.h"
+#include "non-ascii.h"
+#include "sendf.h"
 #include "curl_base64.h"
 #include "curl_ntlm_core.h"
 #include "curl_gethostname.h"
 #include "curl_multibyte.h"
-#include "curl_warnless.h"
+#include "warnless.h"
 #include "curl_memory.h"
 
 #ifdef USE_WINDOWS_SSPI
 #  include "curl_sspi.h"
 #endif
 
-#include "curl_sslgen.h"
+#include "sslgen.h"
 
 #define BUILDING_CURL_NTLM_MSGS_C
 #include "curl_ntlm_msgs.h"
@@ -56,7 +56,7 @@
 #include <curl/mprintf.h>
 
 /* The last #include file should be: */
-#include "curl_memdebug.h"
+#include "memdebug.h"
 
 /* "NTLMSSP" signature is always in ASCII regardless of the platform */
 #define NTLMSSP_SIGNATURE "\x4e\x54\x4c\x4d\x53\x53\x50"