[syslinux] reverted Syslinux resources to vanilla 4.0.5

* also added the full usb.ico from PC Unleashed for future reference

res/syslinux/readme.txt

@@ -1,5 +1,3 @@
-o ldlinux.bss and ldlinux.sys were compiled from the syslinux git tree retreived
-  on 2012.02.13 from git://git.kernel.org/pub/scm/boot/syslinux/syslinux.git
-  with the included .diff applied to be able to use unmodified isolinux config.
-o chain.c32 is from syslinux-4.05/com32/modules:
+o ldlinux.bss and ldlinux.sys are from syslinux-4.05/core/
+o chain.c32 (currently unused) is from syslinux-4.05/com32/modules/
   http://www.kernel.org/pub/linux/utils/boot/syslinux/

res/syslinux/syslinux.diff

@@ -1,28 +0,0 @@
-diff --git a/core/fs/lib/loadconfig.c b/core/fs/lib/loadconfig.c
-index c9652b6..8ed301e 100644
---- a/core/fs/lib/loadconfig.c
-+++ b/core/fs/lib/loadconfig.c
-@@ -10,6 +10,8 @@
-  * This searches for extlinux.conf and syslinux.cfg in the install
-  * directory, followed by a set of fallback directories.  If found,
-  * set the current working directory to match.
-+ * isolinux configuration values are added for the case where ISO
-+ * content has been duplicated to a disk (typically bootable USB).
-  */
- int generic_load_config(void)
- {
-@@ -18,11 +20,14 @@ int generic_load_config(void)
- 	"/boot/syslinux",
- 	"/syslinux",
- 	"/",
-+	"/boot/isolinux",
-+	"/isolinux",
- 	NULL
-     };
-     static const char *filenames[] = {
- 	"extlinux.conf",
- 	"syslinux.cfg",
-+	"isolinux.cfg",
- 	NULL
-     };
-