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

tests/unit/unit1300.c

@@ -21,7 +21,7 @@
  ***************************************************************************/
 #include "curlcheck.h"
 
-#include "curl_llist.h"
+#include "llist.h"
 
 static struct curl_llist *llist;
 

tests/unit/unit1301.c

@@ -21,7 +21,7 @@
  ***************************************************************************/
 #include "curlcheck.h"
 
-#include "curl_strequal.h"
+#include "strequal.h"
 
 static CURLcode unit_setup( void ) {return CURLE_OK;}
 static void unit_stop( void ) {}

tests/unit/unit1302.c

@@ -21,10 +21,10 @@
  ***************************************************************************/
 #include "curlcheck.h"
 
-#include "curl_urldata.h"
-#include "curl_url.h"
+#include "urldata.h"
+#include "url.h" /* for Curl_safefree */
 #include "curl_base64.h"
-#include "curl_memdebug.h" /* LAST include file */
+#include "memdebug.h" /* LAST include file */
 
 static struct SessionHandle *data;
 

tests/unit/unit1303.c

@@ -21,9 +21,9 @@
  ***************************************************************************/
 #include "curlcheck.h"
 
-#include "curl_urldata.h"
-#include "curl_connect.h"
-#include "curl_memdebug.h" /* LAST include file */
+#include "urldata.h"
+#include "connect.h"
+#include "memdebug.h" /* LAST include file */
 
 static struct SessionHandle *data;
 

tests/unit/unit1304.c

@@ -21,7 +21,7 @@
  ***************************************************************************/
 #include "curlcheck.h"
 
-#include "curl_netrc.h"
+#include "netrc.h"
 
 static char login[LOGINSIZE];
 static char password[PASSWORDSIZE];

tests/unit/unit1305.c

@@ -34,11 +34,11 @@
 #define ENABLE_CURLX_PRINTF
 #include "curlx.h"
 
-#include "curl_hash.h"
-#include "curl_hostip.h"
+#include "hash.h"
+#include "hostip.h"
 
 #include "curl_memory.h"
-#include "curl_memdebug.h" /* LAST include file */
+#include "memdebug.h" /* LAST include file */
 
 static struct SessionHandle *data;
 static struct curl_hash *hp;

tests/unit/unit1309.c

@@ -21,7 +21,7 @@
  ***************************************************************************/
 #include "curlcheck.h"
 
-#include "curl_splay.h"
+#include "splay.h"
 
 
 static CURLcode unit_setup(void)