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_rtmp.c

@@ -20,15 +20,15 @@
  *
  ***************************************************************************/
 
-#include "curl_setup.h"
+#include "setup.h"
 
 #ifdef USE_LIBRTMP
 
-#include "curl_urldata.h"
-#include "curl_nonblock.h" /* for curlx_nonblock */
-#include "curl_progress.h" /* for Curl_pgrsSetUploadSize */
-#include "curl_transfer.h"
-#include "curl_warnless.h"
+#include "urldata.h"
+#include "nonblock.h" /* for curlx_nonblock */
+#include "progress.h" /* for Curl_pgrsSetUploadSize */
+#include "transfer.h"
+#include "warnless.h"
 #include <curl/curl.h>
 #include <librtmp/rtmp.h>
 
@@ -37,7 +37,7 @@
 
 #include "curl_memory.h"
 /* The last #include file should be: */
-#include "curl_memdebug.h"
+#include "memdebug.h"
 
 #ifdef _WIN32
 #define setsockopt(a,b,c,d,e) (setsockopt)(a,b,c,(const char *)d,(int)e)