[syslinux] Syslinux docs for core variants and installers

[Gene Cumm]

I'm currently in the process of trying to convert the existing core
documentation (doc/syslinux.txt for starters) to AsciiDoc which can be
used to generate man pages for installed systems, HTML for the website
and possibly cleaner text file output (along with various other
possibilities).  I'm also doing a bit of editing as I go with the
goals of being correct, complete, clear and concise, including new and
deprecated behavior with version numbers noted as there is quite the
wide variation in versions used (although I've never heard of someone
using Syslinx older than 3.00).  My thought here is that if someone is
accustomed to older behavior, this would facilitate them updating to
the new behavior.

Looking at doc/syslinux.txt, there are numerous basic sections.  My
main question is: Should any of these be regrouped into different
documents?  Aspects specific to the installers don't necessarily
concern those using PXELINUX/ISOLINUX.

Aside from the information specific to the command line of the
installers, I see the following sections:

- Name convention
- Config file syntax in subsections (global, label-specifc,
dual-purpose as global or label-specific, and kernel-like directives)
- Non-Linux kernel formats and detection (should this still be
specified outside the config file syntax?)
- Display file format
- Boot prompt command line keystrokes
- Reference to docs covering other variants/sections (pxelinux.txt,
isolinux.txt, comboot.txt; perhaps add menu.txt due to popularity)
- DOS boot (for SYSLINUX on a FAT* file system)(perhaps group with
installer command line)
- Novice protection
- "NOTES ON BOOTABLE CD-ROMS" (perhaps move to isolinux.txt; for the
deprecated FDIMAGE directive / .img floppy image format)
- Hardware compatibility list reference
- (not present) Common problems list reference
- MBR install (bad cat) (perhaps group with installer command line)
- Boot loader IDs
- Bug reports/contact info

I'd think keeping all of the information specific to the command line
of the installers grouped together (covering all installers) would be
useful for people moving between installers.

--
-Gene