Added GRUB docs, Added netboot.xyz

boot/grub/persistent/docs/03_os_specific_notes

@@ -0,0 +1,49 @@
+3 OS-specific notes about grub tools
+************************************
+
+On OS which have device nodes similar to Unix-like OS GRUB tools use the
+OS name.  E.g.  for GNU/Linux:
+
+     # grub-install /dev/sda
+
+   On AROS we use another syntax.  For volumes:
+
+     //:<volume name>
+
+   E.g.
+
+     //:DH0
+
+   For disks we use syntax:
+     //:<driver name>/unit/flags
+
+   E.g.
+
+     # grub-install //:ata.device/0/0
+
+   On Windows we use UNC path.  For volumes it's typically
+
+     \\?\Volume{<GUID>}
+     \\?\<drive letter>:
+
+   E.g.
+
+     \\?\Volume{17f34d50-cf64-4b02-800e-51d79c3aa2ff}
+     \\?\C:
+
+   For disks it's
+
+     \\?\PhysicalDrive<number>
+
+   E.g.
+
+     # grub-install \\?\PhysicalDrive0
+
+   Beware that you may need to further escape the backslashes depending
+on your shell.
+
+   When compiled with cygwin support then cygwin drive names are
+automatically when needed.  E.g.
+
+     # grub-install /dev/sda
+