syslinux on usb key

steps to install syslinux to an usb key. shown here is how to boot memtest.

this assumes $device being the device and $partition being the partition to install syslinux files onto. for example device=/dev/sdx and partition=/dev/sdx1

create a partition on the usb key and mark it bootable.
create a new supported filesystem in this partition. as this is a usb key, vfat seems to be the best option, so: mkdosfs $partition
install syslinux MBR: dd conv=notrunc bs=440 count=1 if=mbr.bin of=$device
install syslinux: syslinux -i $partition
copy the memtest64+ binary, i renamed it to memtest.bin as syslinux seemed to have issues with all the characters. or the fat. or whatever. after renaming it worked.
create $partition/syslinux.cfg (or $partition/syslinux/syslinux.cfg or $partition/boot/syslinux/syslinux.cfg) containing the configuration:
```
   DEFAULT mylabel
   LABEL mylabel
   LINUX memtest.bin
   
```

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